Alan Moses QC, accused ministers and senior civil servants of failing to pass on vital information which could have prevented three innocent businessmen going on trial accused of illegally supplying Iraq's weapons factories.
Mr Moses, who led the prosecution, said he and Customs investigators were left to sift through dozens of Whitehall files to try to discover the truth. Many of the documents were not seen until just before the trial started and some vital intelligence papers were not disclosed at all.
Officials had lots of opportunities to come forward and object to the prosecution but remained silent, he said. 'The position about all this equipment was that 'We knew as near as dammit it was going for military production',' he said. 'I can't understand why the departments weren't saying 'We did know'.'
Mr Moses said that the 'most disturbing' omission was a report from GCHQ, the government listening post, which linked Matrix Churchill to specific Iraqi military projects.
'It seems to me to be the clearest possible indication of knowledge, not just suspicion. I can't understand why on earth I didn't know about this and I don't think I would have gone on with the prosecution if I had.'
Mr Moses, who led the Customs prosecution, said he was 'startled' by the contents of the report when he later saw it. He said Alan Clark, the former trade and defence minister, never disclosed that he may have deliberately encouraged the defendants not to tell the truth about the real purpose of their exports before the trial.
'What has always astonished me is that nobody could have any doubt about the importance of this evidence. You don't sit back and wait and hope it turns out for the best at the trial,' he said.
He was disappointed that people 'who knew exactly the cut of his jib' failed to warn the prosecution of Mr Clark's views and the fact they 'could not rely on what he is going to say'.
Mr Moses said he was also unaware that another key witness, Anthony Steadman - a Department of Trade and Industry official - admitted to colleagues that Mr Clark may have encouraged businessmen to disguise the true purpose of exports.
Had the prosecution known this they could not have gone ahead. 'It is the end of the case if that is the view of the official sitting there.' It directly contradicted his trial evidence, Mr Moses said.
He criticised the Cabinet Office for failing to reveal it had documents vital to the trial which he only gained access to on the weekend before the trial was due to start.
When Mr Moses and an investigating officer were shown into the office of Sir Robin Butler, the Cabinet Secretary, they found a large conference table covered with files. 'We were just left to get on with it. I was furious. What I should have done was to walk out.'
The inquiry continues today.Reuse content