This week marks the 10th anniversary of the parliamentary vote which gave the green light to UK involvement in the US-led invasion of Iraq in 2003.

Ten years on, I think it's crucial for Members of Parliament to reflect on how such a flimsy case for war was able to get through our legal and parliamentary processes.

Writing in the New Statesman on Monday, shadow foreign secretary Douglas Alexander appeared to be in complete denial over the real reasons for the then Labour government taking the UK to war.

According to Alexander, the rationale for the vote was "the capture and removal of weapons of mass destruction that were later proved not to exist".

Yet from the evidence we've seen since, it's clear that the war had nothing to do with finding non-existent Weapons of Mass Destruction, and everything to do with the fact that Prime Minister Tony Blair had already promised President Bush in March 2002 that he would support a war for regime change.

The legal and political distinction between finding WMD and regime change was essential for Blair to secure a majority of the parliamentary Labour party's support for war, without which he could not have gone ahead.

However, the now infamous Downing St memo told Blair in 2002 that in the US "intelligence and facts were being fixed around the policy".

If WMD were really the focus of the war, Blair would have granted the Weapons Inspectors’ call for more time.

Moreover, Blair blatantly misrepresented the evidence available.

For example, in his speech to the House on the resolution to go to war, he suggested that soon after Saddam Hussein’s son in law, Hussein Kamal, defected to the West in the mid 1990s, he disclosed that Iraq had an extensive WMD programme.

In fact, the transcript of the interview with UNSCOM/IAEA records Hussein Kamal’s statements that Iraq’s WMD programme had been destroyed and nothing remained.

The details of the interview were public knowledge in February 2003, well before the vote for war.

The parliamentary failure to hold Blair to account at the time of the vote makes it all the more essential that we have a debate in parliament now.

Given that unwavering Tory support for the vote was so critical, it seems convenient that the current government has failed to find time for the parliamentary debate that I and a cross-party group of MPs requested for this week.

The refusal comes just a few weeks after the leaking of a confidential letter which William Hague wrote to his Cabinet colleagues to tell them not to mention the war.

Whatever position this government now takes on Iraq and the Chilcot Inquiry, it's crucial that the public does not see Parliament just sitting back and ignoring the 10th anniversary of those lies and distortions.

We owe it to the servicemen and women and all those who have lost their lives in Iraq to carefully examine what happened, in order to learn the lessons of the most damaging foreign policy decision of recent times.