The HSE's case raised questions about the role of independent expert witnesses.
The Health & Safety Executive's prosecution of Balfour Beatty and Geoconsult nearly fell apart before the jury was sworn in after the HSE was forced to withdraw a vital WS Atkins report into the collapse.
Defence advocate Arthur Marriott QC nearly derailed the prosecution case when he successfully argued that 82 pages out of 120 in the expert witness report had not been independently prepared by WS Atkins. The report formed a major part of the HSE's £880,000, four year investigation into what prosecuting counsel Hugh Carlisle described as 'Britain's biggest civil engineering failure in the last quarter of a century'.
The Law requires that expert evidence is independent, unbiased and must not omit any information that might detract from its opinion. Marriott relied on documents that he argued showed WS Atkins' head of tunnelling Guy Lance had been influenced by the HSE's principal inspector Martin Thurgood in preparing the report.
'Paragraphs by Thurgood were incorporated verbatim in Mr Lance's report,' said Marriott. 'They were hand in glove in the preparation of the report. Therefore the Lance report is unreliable, dangerous and prejudicial.'
Marriott said the HSE's original incident report into the collapse, which Lance helped prepare, was critical of Heathrow Express client BAA, and its HEX project management team. He claimed that after discussions with the HSE these references were taken out, leaving only references to Balfour Beatty and Geoconsult.
'The report was prepared to give maximum effect to the prosecution,' claimed Marriott. 'Mr Lance's [original incident report] criticises the HEX team and BAA,' said Marriott. 'Those criticisms do not appear in the December 1997 [expert evidence report].' He called for the report to be thrown out by the court but instead an embarrassed HSE chose to abandon it.
The HSE's barrister Hugh Carlisle QC strongly denied there had been any deliberate attempt to direct Lance's opinions: 'Lance says the opinions are his,' Carlisle told the court. 'There was no sinister attempt to turn Lance into a prosecution advocate. There was a misunderstanding of the rules on the use of expert witnesses.' Carlisle said the HSE had employed WS Atkins during its investigation and Lance and Thurgood had been in constant communication.
But removal of the report was a severe blow to the HSE's chances of a successful prosecution. Lance's conclusions formed the core of the HSE case. After the report was withdrawn the prosecution had to elevate former ICE President Sir Alan Muir Wood from the role of supporting witness to primary expert witness. Muir Wood had originally been asked to prepare a brief report into the collapse to support the Lance report.
Marriott said Geoconsult had spent almost £125,000 rebutting the Atkins report and urged the court to punish the HSE. 'The prosecution has an overriding duty to prosecute fairly,' he said. 'They withdrew the Lance report. That should not go without sanctions - deny the prosecution its costs.' On Monday the judge awarded HSE £200,000 costs.
The court was told that the HSE inspector at the centre of the HEX investigation was 'devastated' by the decision to abandon the Lance report.
'We all have something to learn from this incident,' said Thurgood after the trial. 'The fact of the matter was that a close working relationship developed between WS Atkins and the HSE. This compromised the independence of WS Atkins and we must take note of that. The safety of people was, is and always will be our number one priority.'