In a letter to British Prime Minister David Cameron published Thursday, inquiry chairman John Chilcot said the 2-million-word report would be completed by next spring and then ready for the authorities to vet the document for state secrets.

"My colleagues and I estimate that we will be able to complete the text of our report in the week commencing 18 April 2016. At that point, national security checking of its contents... can begin," Chilcot said in a letter to Cameron published on the inquiry's website.

The Iraq War, and, in particular, the role of former Labor Prime Minister Tony Blair in leading the nation into it, are still live political issues in Britain.

Blair makes 'apology' Sunday

The former prime minister apologized Sunday for intelligence failings and planning mistakes around the invasion but insisted he still did not regret the ouster of Saddam Hussein.

"I apologize for the fact that the intelligence we received was wrong," Blair told CNN in an interview.

In a letter to the inquiry chairman, Cameron said he hoped the inquiry would be released without delay.

"I recognize that you have a significant task, but would welcome any further steps you can take to expedite the final stages of the inquiry," read a letter to the inquiry signed by Cameron.

The inquiry has come under repeated criticism from lawmakers and relatives of those killed over how long it has taken. Families of the killed and wounded said they are incensed by the so-called "Maxwellisation" process in which the targets of criticism are given advance copies so that they have a chance to defend themselves.

Reg Keys, whose 20-year-old son Thomas was killed in Iraq, said seven years was too long.

"We, the families, believe that Sir John allowed this ridiculous Maxwellisation process to run on far too long," Keys told the BBC. "It went on for two years when six months would have been fine.

Officially, the inquiry aims to shed light on every aspect of Britain's involvement with Iraq from 2001 to 2009, from the build-up to the US-led invasion in 2003 to the withdrawal of combat troops, and to identify any lessons learned.

Families of military personnel killed in Iraq have threatened to go to take their case to court, saying the delays are prolonging their suffering. About 179 British personnel died in the conflict.

jar/jil (AP, AFP, Reuters)