British Prime Minister Tony Blair has been at pains to deny any linkage between the recent London bombings and the British invasion of Iraq. Geri Peev of the Scotsman reports Blair as saying—

We are not having any of this nonsense about it is to do with what the British are doing in Iraq or Afghanistan, or support for Israel, or support for America, or any of the rest of it. It is nonsense, and we have got to confront it as that.

But Peev noted that MI5, Britain's "homeland security" agency, took a different view just a few weeks ago. According to the MI5 website,

Though they have a range of aspirations and "causes", Iraq is a dominant issue for a range of extremist groups and individuals in the UK and Europe. Some individuals who support the insurgency are known to have travelled to Iraq in order to fight against coalition forces. In the longer term, it is possible that they may later return to the UK and consider mounting attacks here.

MI5 implies a tie between attacks on British interests and 9/11. But unless they're withholding information on other attacks, all the dates appear to be post-invasion—

The bombings in London on 7 July were the first successful attacks in the UK by individuals thought to be associated with international terrorism since the US attacks of 11 September 2001. UK interests have, however, specifically been attacked overseas since then. Al Qaida's car bomb attack on the British Consulate and HSBC in Istanbul in November 2003 killed five people. Al Qaida also claimed responsibility for the shooting of a British national in Riyadh, Saudi Arabia, in September 2004, Kenneth Bigley was murdered in October 2004 in Iraq by a group that has been linked to Al Qaida and a British national was killed by a suicide bomb outside the Doha Players' Theatre in the capital of the Gulf state of Qatar in March 2005.

Well, maybe it was just coincidence.