TONY Blair’s Downing Street ordered a secret memo which said the Iraq war may be illegal to be burnt, a former UK defence secretary has alleged.

Geoff Hoon, who was Labour’s defence secretary for six years from 1999, has insisted that claims the war could have been illegal are not the “nonsense” Blair branded them.

Instead, he alleged to The Daily Mail that there had been a “cover-up” at the highest levels of government.

Jonathan Powell, Blair’s chief of staff, reportedly told Hoon’s staff “in no uncertain terms” that they had to “burn” the memo about the 2003 invasion of Iraq.

The memo was reportedly written by then attorney general Peter Goldsmith, who changed his mind just seven days before the conflict began.

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Hoon said that staff at the Ministry of Defence had been alarmed by the order to destroy the original memo, and defied it by instead locking the paper inside a safe.

However, Powell - who was Blair’s chief of staff from 1995 to 2007 - has denied the allegations.

He claimed that he had sent a separate “minute” from Goldsmith months earlier and asked that that one be destroyed, and that the “attorney general's advice came later”, according to The Daily Mail.

That paper reported that a source close to Hoon insisted that Powell was wrong and that the order had indeed been to burn Goldsmith’s legal advice.

Hoon is a senior Labour figure who has served across top government roles including as transport secretary and leader of the House of Commons.

A memoir he released in late 2021 - titled See How They Run - further attacks Blair. Among other allegations, Hoon claims he was “hung out to dry” and sacked as defence secretary in 2005 as Blair sought to escape blame for the Iraq war.

The Chilcot Inquiry published in 2016 found that the circumstances in which it was decided that there was a legal basis for UK military action in Iraq were "far from satisfactory".

Its damning verdict found Blair’s government had claimed to act for the international community despite knowing it did not have majority support on the UN security council, and that there had been no substantive discussion of the legal issues recorded at Cabinet level.

The news comes as a petition to have Tony Blair stripped of his new knighthood approaches 700,000.

The petition claims the former Labour prime minister was “personally responsible for causing the death of countless innocent, civilian lives and servicemen in various conflicts".

"For this alone he should be held accountable for war crimes," it adds.