By Nick Assinder
Political Correspondent, BBC News website
Kennedy: No "causal link"
It is a question in the front of many minds in Britain - but one few politicians are yet ready to ask in public: Did the war on Iraq increase the likelihood of a terrorist attack on London?
Respect's George Galloway, a vocal opponent of the war, was condemned for stating the London attacks were the price for the war on Iraq. And a small number of Labour MPs have also made the link, albeit more cautiously.
Liberal Democrat leader Charles Kennedy, who opposed the war, has added his voice to the debate declaring he sees no "causal link" between the Iraq conflict and the London attacks.
But he added: "We have to recognise the occupation of Iraq by the multinational force itself contributes to the insurgency and attracts those from abroad who see the opportunity to spread violent fundamentalism.
"And the terrorist certainly will not shrink from using Iraq to increase resentment and as fodder for recruitment."
These sentiments have been slapped down by Downing Street, with spokesmen branding them "naive" and pointing out 11 September happened before the war on Iraq.
But it is probably the Commons question to the prime minister by Scottish Nationalist leader Alex Salmond that finally opened up the debate.
Mr Salmond referred to claims by Italian prime minister Silvio Berlusconi that the US, UK and Italy were more exposed to terrorism because of their leaders' support for the war.
The prime minister dismissed the suggestion, stating: "I think the one thing that is very obvious from the long list of countries who have been victims of this type of terrorism is that it does not greatly discriminate in terms of individual items of policy."
The SNP leader has gone on to expand his case, saying he believed that invasion of Iraq "exponentially increased the number of people throughout the world who can get drawn into this madness and with no direct benefit of destroying terrorist capacity".
Salmond has started the debate
His question was, he insisted, an entirely legitimate one. And it is that fear that the war may have boosted terrorism and the recruitment of terrorists that is bubbling under the current debate.
What no one will declare, needless to say, is "we told you so". Especially at a time when no-one knows who carried out the attacks, or what their motives were.
The prime minister says he believes the bombers were Islamic extremists - and there have been a number of warnings about the likely increase in the terrorist threat to Britain from such people as a result of the war.
During the original Commons debate on Iraq before the war, in February 2003, former Labour minister Frank Dobson said he feared: "Military action in Iraq will be a principal recruiting sergeant for terrorism."
Mr Dobson's London constituency was the site of some of the bomb attacks.
'Wild young men'
In that same debate, Liberal Democrat Simon Hughes argued the risk of terrorism was most likely to be precipitated by US-UK action against Iraq.
His view was supported by ex-Tory minister Douglas Hogg and former Conservative leadership contender Kenneth Clarke.
In an interview after the war, Mr Clarke declared: "We have to make sure that the occupation of Iraq is not the basis for recruitment of lots of wild young men into extremist terrorist groups all over the Muslim world."
Blair rejects any link with Iraq war
His comments came after the powerful Foreign Affairs committee of MPs reported in July 2003: "Al-Qaeda's stance on Iraq may encourage some misguided individuals to try to commit terrorist acts."
Former Labour minister Clare Short, who resigned over the war, had told the committee in evidence that the invasion had led to a "very large" number of recruits to the al-Qaeda network.
In February of the following year the same committee reported: "The war in Iraq has possibly made terrorist attacks against British nationals and British interests more likely in the short term."
And it was later revealed that, before the war, the Joint Intelligence Committee had also warned that military action against Iraq might "heighten", rather than reduce, the terrorist threat to western interests.
The prime minister's response to these warnings has been to point out that 11 September came before the war on Iraq and that the terrorists have shown no discrimination between countries that supported or opposed the war.
He argues that there is plenty of evidence to suggest that terrorism was already on the increase and that he regularly saw, and sees, intelligence reports about the threat to the UK, irrespective of action against Iraq.
UK troops remain in Iraq
His view was echoed by Foreign Secretary Jack Straw in the wake of last year's Madrid train bombing.
"I do not believe we are less safe as a result of the activity we have taken. Over the medium term, still more the long term, we will be much safer."
What the prime minister believes is that the terrorists had, in effect, already declared war on the west.
His actions since then, specifically the war on Iraq, have been designed to avert what he says is his greatest fear - the coming together of weapons of mass destruction and terrorism.
In that, he argues, he is left with no other sensible course of action than to meet the threat head on in the determination to win the war on terror, no matter how long it may take.