LONDON - A further delay in a report into Britain’s role in the Iraq war sparked angry claims of a cover-up on Wednesday, illustrating the lingering controversy over a conflict in which 179 British soldiers died.

Six years after the inquiry started and 12 years on from the 2003 war, its chairman John Chilcot said there was “no realistic prospect” of delivering the report before May’s general election.

The delay is linked to individuals including former prime minister Tony Blair being given the chance to respond to criticism of them in the report. Chilcot, a former senior civil servant, wrote to Prime Minister David Cameron that this process would take “some further months”.

The report is unlikely to influence the outcome of this year’s knife-edge general election as Cameron’s Conservatives were in opposition at the time, while Blair and other senior members of his Labour government are no longer in frontline politics.

But questions over Britain’s role - and particularly whether Blair’s government “sexed up” an dossier on Iraq’s weapons of mass destruction to make the case for war - are still the subject of heated debate.

The Chilcot inquiry was set up in 2009 by Blair’s successor as prime minister, Gordon Brown, and was originally due to report within a year.

Current deputy prime minister Nick Clegg said in a letter to Chilcot that the public would find the latest delay “incomprehensible”.

“There is a real danger the public will assume the report is being ‘sexed down’ by individuals rebutting criticisms put to them by the inquiry, whether that is the case or not,” he added.

Rose Gentle, whose son Gordon was killed fighting in Iraq in 2004, told the BBC that she and other families were “really frustrated” that it was taking so long. “We just feel constantly let down. We can’t get over something like this until we find out,” she added.

A previous sticking point around whether notes from Blair to then US president George W. Bush would be published has been resolved, it emerged Wednesday.

Chilcot said that 29 of these would now be published with the final report, “subject to a very small number of essential redactions”.

Blair’s office did not immediately respond to a request for comment but he has previously denied seeking to slow down publication of the report. Lawmakers are expected to hold a debate in the House of Commons on the issue next week.

David Davis, a senior Conservative lawmaker leading the move, said the delay was “not good enough”. “We need to know why. This is not simply some formality,” Davis told the Guardian newspaper. “This is for the whole country to understand why we made a terrible mistake in Iraq,” he said.

Cameron had wanted the report published before the election but said in reply to Chilcot’s letter that, since the report was independent of government, he would “respect” the decision.