Michael Heseltine managed to fend off Labour demands for a judicial inquiry without specifically mentioning his Cabinet colleague or BMARC, the weapons company of which Mr Aitken was a non-executive director, in a 30-minute speech.
However, with Mr Aitken sitting further along the government front bench, Mr Heseltine disclosed he had set in train inquiries into arms exports before receiving the MP's questions that led to last week's extraordinary statement on BMARC.
"As a result of further details we became convinced that there was a need to bring to the Commons fuller information which would mean earlier information given to the House would have to be modified," Mr Heseltine said. Labour MPs pressed, without success, to know what the additional information was.
Mr Aitken, a director for two years from 1988, has repeatedly denied any knowledge that naval guns made by the company were being shipped to Iran via Singapore. Mr Heseltine reopened the affair when he conceded intelligence reports available at the time showed the guns could have been destined for Iran, in breach of an embargo.
Opening the debate, Jack Cunningham, Labour trade and industry spokesman, said Mr Aitken was recruited by BMARC because of his knowledge of the Middle East. At least three former directors had stated publicly that all directors were regularly briefed on Project Lisi.
"Are we to believe that a man who says he took his non-executive duties seriously did not see fit to press his fellow directors as to the real nature of Project Lisi - a project under which naval cannon were ordered by Singapore despite the fact that the Singaporean navy did not have enough boats capable of mounting a fraction of the weapons provided? It is a basic principle of company law that a non-executive director has the same obligations and is subject to the same liabilities as any other director."
Mr Cunningham added: "The fact that Mr Aitken may have not bothered finding out the basic facts of one of his company's largest orders does not excuse him. He failed in his duties as a non-executive director - and the same is true of ministers and their departments."
Mr Heseltine, speaking of the time of the Iran-Iraq war, said nobody would want to defend the way export licences were approved, but there was no point in setting up a judicial inquiry to go over ground already covered by Sir Richard Scott.
There was a "public interest" in seeing the Scott inquiry, which had already taken three years, brought to a conclusion.
Mr Heseltine repeated his call for a inquiry by the Commons select committee on trade and industry, but Richard Caborn, the committee's Labour chairman, warned that might go ahead only if full DTI and intelligence service information was made available.
Mr Caborn said the committee's report on Project Babylon, the export of parts for the Iraqi supergun, was "inconclusive" because it did not have access to such the information.
The committee will take a decision tomorrow on whether to hold an inquiry. However, as Mr Caborn set out his demands, he was warned by Sir Cranley Onslow, a senior Tory on it, not to assume he was speaking for all.
Winding up the debate, Ian Taylor, Under-Secretary for Trade and Industry, said certain documents needed to be handled with caution. "Revealing intelligence sources does risk lives and any government needs to depend on its intelligence sources."
Sir Nicholas Bonsor, Tory chairman of the defence select committee, criticised the Independent, which was "normally reliable and accurate" but yesterday had "one of the most appalling and inaccurate headlines I have read in the media".
He said the headline had stated papers [rediscovered by the MoD police] showed Mr Aitken knew about the arms deal, but there was nothing in the text of the article to support it and Mr Aitken had categorically denied it. "For a national newspaper to make a headline of that kind is irresponsible and is journalism of the worst kind."
Nigel Jones, for the Lib Dems, congratulated the media on their digging. "If we are to avoid the kind of trial by media the Chief Secretary so abhors, then the plethora of unanswered questions ... must be answered in the appropriate forum."
In a trenchant defence of Mr Aitken, Edward Leigh, a former trade and industry minister, who has talked to former directors and trade union representatives at the Lincolnshire-based company, said nobody, including Mr Aitken, could have "any clue at all" that the guns were going anywhere expect Singapore. The contract had been inherited from the Swiss company Oerlikon, previous owners of BMARC and Singapore already possessed the guns.
Urging MPs to support Mr Aitken, he said: "He has given his word to this House. He is a much-admired and competent minister. We should accept it."
The Treasury Chief Secretary was a "victim of a discreditable witch-hunt by the Opposition and the media. He should stand his ground so that truth and honour will be the touch-stone by which we conduct our affairs, not personal vindictiveness and innuendo," Mr Leigh added.
Labour's motion calling for an independent judicial inquiry was defeated by 291 votes to 267.Reuse content