01/05/02 - Report of David Bristowe regarding mobile telephone evidence

SUMMARY OF OPINION

1. The Criminal Cases Review Commission (CCRC) are presently reviewing the case of Mr Michael Steele who, with Mr Jack Whomes, has been convicted of murder.

2. In January 2002 Mr N J Price, the Case Review Manager posed a question relating to mobile "phone evidence given at the trial:- "Given the evidence you (David Bristowe) gave at the trial regarding the effect on telephone signals of foliage, to what degree are your original findings enhanced by the latest tests carried out under similar foliage conditions?" I have addressed this point within this report. In my opinion any effects of foliage on the transmission between a mobile 'phone used in Workhouse Lane and the Hockley cell site would have been very small compared with the effects of a significant hill which is directly In the line of sight between the two points.

3. My subsequent tests, under foliage conditions similar to those at the time of the murder confirmed the results of the tests which I made before the trial. In my opinion, my earlier findings are "enhanced" in that any doubt as to the validity of the earlier tests, as a consequence of differing foliage conditions, has been eliminated.

4. Mr Price also posed the question:- "To what degree are your original findings enhanced by the use of Mr Whomes' mobile 'phone, compared to the equipment used in the tests before the trial?"

5. I had always believed that the best way to carry out the tests was to use Jack Whomes' own 'phone but this was not possible before the Trial. My original results were carried out with equipment which I acknowledged might not respond to the different levels of service provided by the local cell sites in the same way as a mobile 'phone. In my opinion, my original findings have been "enhanced" by the subsequent use of a mobile 'phone to make test calls, and the assistance of Vodafone to analyse the test results. The validity of the test results is further enhanced by the use of Jack Whomes actual 'phone.

6. I maintain the view that the use of the Hockley 54/3 cell identity is consistent with the suggestion by the Defence that Jack Whomes 'phone was used at the Wheatsheaf, but not consistent with the Prosecution assertion that at 18:59 on December 6th 1995 the 'phone was used in Workhouse Lane.

David Bristowe BSc,CEng,MIEE,MAE
1 May 2002

CONTENTS

1. INTRODUCTION 1
2. THE TRIAL 4
3. SUBSEQUENT TESTS 6
4. SERVICE FROM THE HOCKLEY CELL SITE 7

Figure 1
A section of an Ordnance Survey Map showing the line of sight paths between the Wheatsheaf Public House and Workhouse Lane, and the Hockley Cell Site.

Figure 2
An enlarged section of the Ordnance Survey Map showing the line of sight paths near the Wheatsheaf and Workhouse Lane, in greater detail.

Expert Report relating to Additional Mobile
'Phone Evidence in the case of R -v- Steele and Whomes

1. INTRODUCTION

1.1. In January 1998 Michael Steele and Jack Whomes were sentenced to life imprisonment for the murders of Pat Tate, Tony Tucker and Craig Rolfe.

1.2. Part of the evidence at the trial related to the use of mobile 'phones by Michael Steele and Jack Whomes, and by Darren Nichols who claimed to have driven Steele and Whomes to Workhouse Lane, Rettendon, in the early evening of December 6th 1995.

1.3. During the course of the Trial the Prosecution introduced evidence in the form of telephone call detail records given in Court by various representatives of the mobile 'phone companies Cellnet, Vodafone and Orange. Solicitors acting for the two Defendants instructed Forensic Engineering Associates to examine the call detail records and to prepare Expert Evidence reports.

1.4. I, David Bristowe, prepared two reports and I subsequently gave evidence in the Trial.

1.5. My first report dated August 30th 1997 included a theoretical analysis in respect of the Cellnet mobile 'phone 0860-853978 used by Michael Steele, and a similar analysis of calls made on the Vodafone mobile 'phone 0836-215646 used by Jack Whomes. I also examined call detail records relating to Darren Nichols' 'phone 0973-427288, used on the Orange network.

1.6. Following my theoretical analysis I concluded that the telephone evidence was not inconsistent with the explanations put forward by the Defendants that around 18:00 on December 6th 1995 Michael Steel's 'phone was used close to the village of Bulphan, and at 18:59 Jack Whomes' 'phone was used in the car park of the Wheatsheaf public house in Rettendon.

1.7. On a theoretical basis, the telephone records for the two 'phones were also not inconsistent with assertions by the Prosecution, that at 18:00 Michael Steel's 'phone was used at the Halfway House public house in Childerditch and at 18:59 Jack Whomes' 'phone was used in Workhouse Lane, Rettendon.

1.8. I was less inclined to accept the assertion by Darren Nicholls that the service provided to his Orange 'phone in the car park of the Wheatsheaf public house was very poor. The Orange cell site at Rettendon is in line of sight and less than 2 kilometres distant from the Wheatsheaf public house. I would have expected a good service from the Orange network at that location. Furthermore Darren Nicholls claimed to have been in Meadow Road, Rettendon when he received the calls from Jack Whomes at 18:59. These calls were served by the Orange cell site at Basildon, which is not the closest site and not the site which I would have expected to provide best service to an Orange 'phone in Meadow Road.

1.9. Following the issue of my first report I was instructed by the Solicitors acting for the Defence to carry out practical measurements to see if it was possible to determine whether it was more likely that Jack Whomes "phone was used at the Wheatsheaf or in Workhouse Lane, and whether Darren Nicholls version of events was credible. I carried out these tests on September 17th and September 24th 1997.

1.10. To evaluate the service provided by the Orange network I was able to engage the services of Mr David Cole, an Orange Field Engineer who brought with him a comprehensive test set suitable to measure, at any location, the service provided from each of the local Orange cell sites.

1.11. The results of my tests are contained in a report dated September 26th 1997. We found that the Orange network offered a good level of service at the Wheatsheaf car park. For Meadow Road, although at most points the service provided by the Basildon cell site was inferior to that offered by other local sites the Basildon site service was nevertheless generally adequate to provide a service. I cannot dismiss Darren Nicholls claim, that he was in Meadow Road when he received Jack Whomes' call.

1.12. I have been told that Jack Whomes says that he made two attempts to call Darren Nicholls at around 7 pm on December 6th 1995, but that each call "failed". The call records show the first of these two calls as having been made at 18:59:21, via cell identity 724/1, the Sector 1 antenna of the cell site 724 at Baker's Wood, Ingatestone. The call lasted just one second. The second call, at 18:59:32 was served by cell identity 54/3, the Sector 3 antenna of the Hockley cell site and lasted for four seconds.

1.13. Jack Whomes says he tried unsuccessfully to call Darren Nicholls from the car park of the Wheatsheaf to tell him that he had successfully loaded his (Nicholls') broken down car onto a car transporter trailer. The Prosecution alleged that Jack Whomes was then in Workhouse Lane, and the four second call was of sufficient duration to tell Darren Nicholls to return to the Lane to pick up him up, together with Michael Steel.

1.14. In December 1995 the service provided by the Vodafone analogue mobile 'phone in the Rettendon area was poor such that calls were likely to fail. I needed however to examine the service provided at each of the two locations from cell identity 724/1 (Ingatestone), and cell identity 54/3 (Hockley).

1.15. I was unable to obtain the services of Vodafone to carry out a survey and I carried out the measurements myself. The test equipment I used was a radio communications receiver able to be set to the particular frequencies of the analogue mobile 'phone service. I took measurements at the Wheatsheaf and at Workhouse Lane.

1.16. The measurements indicated that both Ingatestone 724/1 and Hockley 54/3 could provide service, albeit a poor service, to a Vodafone mobile 'phone at the Wheatsheaf. Also, at the entrance to Workhouse Lane I detected the control channel from Ingatestone 724/1 at a level which I felt would be adequate to provide service. However I had difficulty in detecting a service from Hockley 54/3 anywhere along the Lane. Where I did detect a signal from Hockley 54/3 it was at a signal level considerably beneath the levels offered by other local cell sites. I believed it very unlikely that the user of a Vodafone analogue mobile 'phone in Workhouse Lane would ever be served by the Hockley 54/3 service.

1.17. If the measurements which I took in September 1997 were representative of the conditions on December 6th 1995 my tests suggest that Jack Whomes was not in Workhouse Lane when he made the call to Darren Nicholls at 18:59.

1.18. In my opinion the reason that Hockley 54/3 cannot be detected in Waterhouse Lane is clear-cut. There is a hill in Rettendon to the south of Workhouse Lane which effectively blocks the line of sight path between the user of a 'phone in Workhouse lane and the cell site antenna which is mounted on a water tower in Hockley. Although cellular 'phone radio signals are to some extent diffracted (bent) over a hilltop, as far as radio waves are concerned Workhouse lane falls within the "shadow" of the hill. The same is not true of the Wheatsheaf which has a clearer line of sight to the Hockley cell site.

1.19. I carried out a similar exercise in relation to Michael Steele's 'phone calls made to Jack Whomes at 18:03 and 18:09 on December 6th 1995. Both calls were served by the BT-Cellnet cell site 0854 at Childerditch. I was told that Michael Steele had said that when he made the calls he was in or close to the village of Bulphan. Conversely, the Prosecution alleged he was in the car park of the Half Way House public house.

1.20. I indicated the results of my tests in a report dated 4th November 1997. In my opinion the calls could well have been made close to Bulphan but it was unlikely that they could have been made from the Halfway House. Just as Waterhouse Lane is screened from the Hockley cell site by the Rettendon Hill, so the Halfway House is shielded from the Childerditch site by raised ground known as Jury Hill.

2. THE TRIAL.

2.1. At the Trial Simon Collins of Orange gave evidence showing the possible use of Darren Nicholls' 'phone in the Rettendon area at 18:48 and 18:59. Robert Foxwell of Vodafone showed that Jack Whomes 'phone could have been used near Rettendon at 18:59, and Dennis Clayton of BT-Cellnet showed the use of Michael Steel's 'phone in the general area of Childerditch. I am not aware that any of these views were challenged by the Defence.

2.2. Cell site analysis is not an exact process. However, although I could not disprove the Prosecution's view of events, the call detail records for Jack Whomes' 'phone and for Michael Steel's 'phone were, in my opinion more consistent with the explanations put forward by the Defendants than with the claims made by the Prosecution.

2.3. I was aware that it might be argued in Court that the measurements I had carried out, and the conclusions I had drawn had certain weaknesses.

2.3.1. The Vodafone service might have changed between the time of the murder and my tests, to the extent that my tests were invalid.

2.3.2. The test equipment which I had used to assess the level of service at the Wheatsheaf and at Workhouse Lane was of good quality but was uncalibrated. Furthermore the reception characteristics of the scanning receiver which I used are not properly representative of an analogue mobile 'phone.

2.4. I had addressed these two points

2.4.1. In December 1995 Vodafone were in the process of updating their service from the older (TACS) analogue mobile 'phone system to the present day (GSM) digital system. I had received assurances from Vodafone that although the analogue service was being maintained, with the advent of the digital system the analogue service was not being up-graded. It was reasonable to assume that as far as the Vodafone system was concerned the state of the Vodafone system at the time of my tests was representative of the system at the time of the murder.

2.4.2. The ideal method to indicate whether Jack Whomes 'phone could have made the call at 18:59 from Workhouse Lane was, in my opinion to make a series of calls, using a Vodafone mobile 'phone, at each of the two locations and from the call detail records note which cell sites served the calls at each location. The characteristics of mobile 'phones vary from model to model and to a lesser extent between different samples of the same model of 'phone. It was for this reason that I attempted to obtain Jack Whomes' own 'phone to reduce any uncertainties concerning the tests. Unfortunately my Instructing Solicitors were unable to obtain the release of Jack Whomes' 'phone from the Essex Police.

2.4.3. I was not unduly concerned. At the Wheatsheaf I had detected what I believed to be poor but probably adequate signal levels both from Ingatestone 724/1 and from Hockley 54/3. My test equipment could not determine the quality of service from these two cell identities but there was no doubt in my mind that signals from both cell identities could be received at the Wheatsheaf. On the other hand the signal I had detected from Hockley 54/3 in Workhouse lane was very weak and considerably beneath the levels of signals from other local cell sites, such that I felt confident that the user of a Vodafone analogue mobile 'phone in Workhouse Lane would not be served by Hockley 54/3.

2.5. In Court the Prosecution suggested to me that my results were not truly representative, particularly because the tests had been carried out in the autumn, when there were leaves on the trees, and the murder took place in the winter when there were fewer leaves. I was asked whether foliage affected the passage of mobile 'phone signals and I confirmed that foliage did marginally affect the passage of radio signals. (Strictly it is the presence of moisture in the leaves which causes any attenuation of radio signals).

2.6. In deeply forested conditions the attenuation of 'phone signals by the foliage might be significant, but in my view the effects of any foliage in that part of Essex would be very small compared with the fact that between Hockley and Workhouse Lane there is a significant hill which blocks the signals far more effectively than any foliage. The same is true to a lesser extent between the BT Cellnet cell site at Childerditch and the Halfway House where the signals are degraded by the presence of Jury Hill.

2.7. I have subsequently had the opportunity to examine a transcript of that part of the summing-up by Mr Justice Hidden which dealt with the telephone evidence. Whilst the Judge's summing up is generally in accordance with what I remember of my evidence it did not, in my view, convey the points which I had hoped to put over, namely that my interpretation of the evidence of the call detail records for December 6th 1995 was that:-

(a) if Jack Whomes 'phone had been used in Retterndon at 18:59, it might have been used at the Wheatsheaf but it is very unlikely that it was used in Workhouse Lane.

(b) if Michael Steel's 'phone was used in the vicinity of the Childerditch cell site at 18:03 and 18:09 it might have been used close to Bulphan, but it is unlikely that it was used at the Halfway House.

(c) Darren Nicholls statement of his whereabouts at 18:59 was unlikely to be correct.

3. SUBSEQUENT TESTS

3.1. After the Trial, for my own satisfaction, I wanted to repeat my tests using Jack Whomes actual 'phone. My Instructing Solicitors had difficulty in persuading the Essex Police to release the 'phone but it was eventually agreed that I could have the 'phone for a strictly limited period, subject to my giving an undertaking that the 'phone would not be adjusted or modified in any way. Officers of the Essex Police then assisted me in replacing the failed 'phone battery and in charging the new battery prior to my tests.

3.2. I was anxious that the independent nature of my tests should be totally beyond question, and I asked that an Officer from Essex Police should witness the tests. This was not possible, but I was fortunate to obtain the help of Mr John Little, a local Councillor who agreed to oversee the tests. Vodafone gave their assistance in putting Jack Whomes' 'phone back "on line" and in agreeing to provide me with copies of the call detail records.

3.3. Despite my belief that in this case foliage had little effect on the propagation of the 'phone signals I arranged for the tests to be carried out on 18th January 2000, when the foliage conditions were similar to the conditions at the time of the murder. Also, to the best of my knowledge, the Vodafone (TACS) analogue 'phone system had remained unchanged since the date of the murders.

3.4. The tests were carried out:-

(i) with Jack Whomes' 'phone which had been stored by the Police since his arrest,

(ii) with the Vodafone TACS system unchanged, and

(iii) at the same time of year as the murder. The tests were, I believe , carried out under conditions closely representative of the conditions at the time and date of the murders.

3.5. The results of the tests are contained in my report dated 22nd February 2000. Of a total of twenty calls made at various locations in the car park of the Wheatsheaf seven were served by Hockley 54/3, and three by Ingatestone 724/1. The remaining ten calls were served by other cell sites in the Chelmsford area including five calls served by Hockley 54/1, the north east facing antenna of the Hockley cell site.

3.6. Of a total of forty one calls made from different points along the relevant length of Workhouse Lane fifteen were served by Ingatestone 724/1. There were no calls served by Hockley 54/3. The remaining 26 calls were served by other cell sites in the Chelmsford area including 4 calls by Hockley 54/1.

3.7. I should emphasise that the tests were carried out "blind", in that there was no way I or anyone else could have known which cell site would serve Jack Whomes' 'phone at the particular point in Workhouse Lane where the 'phone was used for each test call. The actual cell site used was not known until Vodafone were able to analyse the data approximately one month after the tests took place.

3.8. Jack Whomes' 'phone was returned to the Essex Police on the completion of the tests on January 18th 2000.

3.9. When the results of the tests were received they served to confirm my earlier views, that when Jack Whomes made his call at 18:59 on 6th December 1995 he might well have been in the car park of the Wheatsheaf but it is very unlikely that he could have been in Workhouse Lane.

4. SERVICE FROM THE HOCKLEY CELL SITE

4.1. In my report on the tests which I carried out with Jack Whomes 'phone (dated February 2000) I showed that although none of the test calls made from Workhouse Lane were served by Hockley 54/3, the cell site used by Jack Whomes at 18:59 on December 6th 1995, a small number (4/41) of the test calls made from Workhouse Lane were served by cell identity 54/1, the Sector 1 antenna of the Vodafone Hockley cell site.

4.2. The basic configuration of each cell site on the Vodafone analogue (TACS) included three transmitting antennas, with each antenna providing service over a nominal 120 degrees around the site, that is to say plus and minus 60 degrees around the "boresight" or mid point of the coverage angle. In practice the best coverage was provided over some +/- 40 degrees with reduced coverage up to +/- 70 degrees.

4.3. There was a "nominal" arrangement for the Vodafone analogue cell sites in which the three antennas were directed as below:-

Sector Boresight Angle
Sector 1 90 degrees (due east)
Sector 2 210 degrees (approximately south west)
Sector 3 330 degrees (approximately north west)

In practice the antenna angles of any particular cell site could vary significantly from the nominal values.

4.4. In carrying out my analysis prior to the Trial I had been advised by Vodafone that the antenna of the Hockley Sector 3 service was directed at a compass angle of 330 degrees, the standard angle for a sector 3 antenna. However I was also provided with coverage plots for Hockley 543 which suggest that the true orientation of the antenna might have been closer to 310 degrees.

4.5. In my view it is perfectly clear why Jack Whomes 'phone would not have been served by Hockley 54/3 if he was in Workhouse Lane. There is a hill between Workhouse Lane and the Hockley cell site which effectively blocks the line of sight path to the cell site. I now produce my Figures 1 and 2, copies of part of an Ordnance Survey map of the area. The map shows the hill at Rettendon Hail and the New Hall Fruit Farm. I have plotted the profile of the land between Workhouse Lane and the Hockley cell site and note that this hill effectively shields Workhouse Lane from the Hockley cell site. The car park at the Wheatsheaf has a clearer (though still not perfect) line of sight to Hockley.

4.6. I remain unsure of the means whereby signals from the Hockley 54/1 antenna were able to reach Workhouse Lane. I have recently been in contact with Vodafone but have been advised that there are now no records available to indicate the orientation of this antenna in 1995.

4.7. The radio signals which make up the communication path between the cell site and the handset are subject to reflection from solid objects including the terrain itself. In fact "multipath" interference, a phenomenon which occurs when the signal from the transmitter to the receiver arrives via several reflected paths in addition to the direct path, can cause significant problems in the modern GSM (digital) service.

4.8. I have concluded that the unexpected service from Hockley 54.1 which I found in my January 2000 tests in both at Workhouse Lane and at the Wheatsheaf, must have come about as a result of reflection from some geographical feature. It is an unfortunate fact that the Vodafone analogue service has been discontinued, and the modern GSM antennas on the Hockley cell site have different orientations. I do not believe that the reasons for the apparently anomalous service from the Hockley 54.1 antenna, which I found in January 2000 at the Wheatsheaf and at Workhouse Lane, can now be established.

4.9. Nevertheless this does not modify the opinion, which I have expressed throughout, that whereas my tests have indicated that the records of Jack Whomes' 'phone calls at 18:59 on December 6th 1995 are consistent with his being at the Wheatsheaf, my tests do not support the Prosecution assertion, that the calls were made from Workhouse Lane.