Wall said the actions by Blair and Campbell meant there was no possibility of a UN compromise to avert the war.

Wall is one of a number of key political and military figures interviewed for documentary-maker Michael Cockerell's three-part BBC 2 series on Blair, which continues this week. Wall accompanied the Prime Minister to a crucial EU summit in October 2002 as Blair and US President George W. Bush were becoming increasingly isolated. He said that Chirac privately urged caution, even using the Prime Minister's then-infant son to bolster his argument, saying: 'Leo will not thank you if you take Britain into war.'

Later on, according to Wall, Chirac argued strongly that 'while Saddam Hussein could be overthrown, the subsequent consequences would be disastrous'. But the policy aide reveals: 'Tony Blair never paid any attention to what Chirac said... He'd kind of come out rolling his eyes and say: "Oh dear, dear old Jacques, he doesn't get it, does he?"...'

Blair and his press chief Campbell reportedly decided to place the blame for deadlock squarely on Chirac, following a breakdown of diplomatic efforts to get a second Security Council resolution that could have delayed an invasion.

'I recall the moment,' Wall says in the documentary, 'because I happened to be in the corridor in Number 10 when he and Alastair Campbell were walking down the corridor and they decided effectively to play the anti-French card. They'd been given an opportunity to do so because President Chirac had given a broadcast interview the previous day in which he said that, as of that moment, France would veto a resolution authorising war.'

Wall says it was clear that Chirac had not ruled out the possibility of future French support for such a compromise.

This week's second instalment in the series, titled 'A Man with a Mission', paints a picture of a Prime Minister convinced as a matter of personal faith that the Iraq war was right. It also quotes Sir Jeremy Greenstock, British ambassador to the UN in the run-up to the war, as stating that Blair 'took his eye off the ball' when it came to ensuring improvements in Iraq once the invasion was over.

Campbell does not appear on the programme, but another former Downing Street aide, Peter Hyman, offers a humorous take on the degree to which insiders felt growing pressure over the Blair-Bush 'special relationship'. Hyman recalls the Prime Minister asking Campbell for advice on how to begin a speech to the nation on the decision to go to war. Campbell reportedly said: 'Do not start with "my fellow Americans"?' Blair, clearly unamused replied: 'Your sense of humour may get you in trouble one day.'