The long-awaited inquiry report which runs to 2.6 million words also said Britain had joined the US-led invasion of Iraq in 2003 without exhausting peaceful options, that the legal basis for military action was not satisfactory, and that the planning was wholly inadequate.

The inquiry rejected Blair’s view that Iraq’s post-invasion problems could not have been known in advance. The inquiry’s purpose was for the British government to learn lessons from the invasion and occupation that followed, in which 179 British soldiers died.

Opponents of Blair’s decision to join the war will pore over the report for its judgment on how the Labour leader, who quit in 2007, justified the military action. At the time, he said intelligence showed that Saddam had weapons of mass destruction but after the invasion none was found.

Public hearings, including two appearances by Blair, ended in 2011 but since then the writing of the report has been dogged by rows over the release of secret government files and the contacts between London and Washington. It includes details of notes from Blair to Bush and quotes from more than 130 records of their conversations.

Critics believe Blair, who sent 45,000 British troops for the invasion, gave Bush an unconditional promise that Britain would join military action and that he then distorted intelligence to back this up and put pressure on government lawyers to give the invasion legal approval.

After the report was published, Blair has expressed regret and said,

”For that decision today I accept full responsibility, without exception and without excuse. I recognise the division felt by many in our country over the war and in particular I feel deeply and sincerely – in a way that no words can properly convey – the grief and suffering of those who lost ones they loved in Iraq, whether the members of our armed forces, the armed forces of other nations, or Iraqis.”

Below are some of the report’s key findings:

• The circumstances in which it was decided that there was a legal basis for UK military action was found unsatisfactory.
• The legal advice produced by the government’s top lawyer was presented to a cabinet meeting of senior ministers, but was not discussed in detail.
• The report criticized the way Prime Minister Tony Blair presented intelligence information to the public
• At no stage was the proposition that Iraq might no longer have chemical, biological or nuclear weapons or programmes identified and examined by either the JIC or the policy community.
• The report said that Britain chose to join the invasion of Iraq before peaceful options for disarmament had been exhausted
• Blair was warned about the threat of increased al-Qaida activity as a result of the invasion, the report said.