Former prime minister Tony Blair has denied reports in the British press that obstruction on his part is one reason that a report on how and why Britain joined the Iraq War took nearly seven years to complete. (Dan Kitwood/Getty Images)

It has been more than 13 years since British troops stormed their way through the Iraqi desert in a quest, alongside their American allies, to topple the dictator Saddam Hussein.

It has been more than seven years since the last British combat troops lowered the Union Jack and withdrew, their prime minister hailing Iraq as a “success story” as they left.

But it will not be until Wednesday that the British public gets what war critics say was owed long ago: an exhaustive account of how and why the U.K. government opted to join the invasion, setting off a chain of conflict that rages to this day.

The account will come in the form of a staggering 2.6 million-word report, part of an official inquiry that itself is nearly seven years old and has involved unfettered access to documents and witnesses. The report will address Britain’s decision to go to war, as well as its role in a conflict that left 179 British troops and tens of thousands of Iraqis dead.

[Tony Blair kind of apologized for the Iraq war, but many Brits still hate him]

The findings of the investigation, led by a retired British diplomat, John Chilcot, could be especially damaging for former prime minister Tony Blair and other top British officials who in 2003 made the call to join the United States in a war sold to the public with claims that Hussein’s arsenal contained weapons of mass destruction. No such weapons were ever found.

“What we will get is hard evidence of the failures, deceptions and arrogance involved in this war,” said Jane Kinninmont, a senior research fellow at the London-based think tank Chatham House. “It will be almost impossible for the report not to come out with very heavy criticisms.”

What will not be known until the report’s publication, however, is the extent to which it finds that senior officials, including Blair, knowingly misled the public. “That’s the big question that still remains,” Kinninmont said. “To what extent will there be personal culpability assigned to senior politicians and policymakers?”

[Tony Blair feels bad about the war in Iraq. But he still wants to try it again.]

Although the report was not set to be published until Wednesday and its contents have been kept strictly secret, members of Parliament have already raised the idea of formally censuring Blair, perhaps through an impeachment vote that could bar him from holding office again.

The embattled leader of Blair’s Labour Party, Jeremy Corbyn, has even said he could support war-crimes charges against the former prime minister. The International Criminal Court has indicated that that is extremely unlikely.

Whatever the findings, the inquiry is unlikely to substantially change perceptions of a war that only one in four Britons rate as a success. Public outrage over the war — and particularly over a belief that the country was lied to in the lead-up to the invasion — remains an open wound in British politics.

It was a wound exploited last month by campaigners arguing for a British exit from the European Union. “Leave” politicians dismissed the consensus of experts who argued against the departure, calling it an establishment-organized conspiracy on par with the government’s “sexed up” case for war in Iraq. Cynically minded voters appeared to agree.

[The man who took a sledgehammer to Saddam’s statue wants him back]

The Chilcot inquiry, as it is known here, lands as the country is digging out of the political wreckage from that E.U. referendum. Both major parties are in chaos, with Prime Minister David Cameron on his way out and Corbyn refusing to budge despite a mass mutiny among Labour members of Parliament.

Although the report does not factor directly into that upheaval, it will certainly do little to quiet the suddenly turbulent waters of British politics.

Any attempt to punish Blair, who led the country for a decade, could prove especially contentious. One of the chief fissures in the Labour Party is between those who want to emulate his model of electoral success and those who detest him for his role in Iraq.

Blair has said he cooperated with the inquiry and has denied persistent reports in the British press that his obstruction is one reason the report took nearly seven years to complete, rather than the original plan to do it in one.

In an appearance Sunday on Sky News, he refused to be drawn into commenting on the report’s substance, saying, “We should wait for the report to be published, and then I will express myself.”

Blair has in the past blamed faulty intelligence, while arguing that the world is better off without Hussein even if he was not stockpiling weapons of mass destruction.

[British intelligence warned about Iraq War]

The Chilcot report was commissioned by Blair’s successor, Gordon Brown, who vowed that “no British document and no British witness will be beyond the scope of this inquiry.”

At 2.6 million words, the report clocks in at three times the length of the complete works of William Shakespeare, or five times that of Tolstoy’s “War and Peace.” It is expected to include memos that Blair sent to then-President George W. Bush — though not the replies.

Many senior British officials have previously sought to blame Washington for the rush to invade Iraq in the spring of 2003. Although the United States led the war effort, there has been no comparably ambitious fact-finding mission addressing U.S. decision-making.

More than 1,000 original documents will be included in the British findings. In addition to reviewing the actions of officials, the report will examine the conduct of British troops in the field.

Kinninmont said that even if the report doesn’t change minds about the war, it may harden existing attitudes, including cynicism toward public officials and a reluctance to endorse military action overseas.

That reluctance has already shaped Britain’s approach to the war in Syria. Parliament opted out of a plan to bomb the forces of President Bashar al-Assad in 2013 and later delayed getting involved in a U.S.-led air campaign against the Islamic State. Both decisions were heavily influenced by the country’s experiences in Iraq.

The Chilcot findings, Kinninmont said, could help to “ensure that there is a toxic political environment for the next prime minister to take the country to war, just as there was for this one.”

Read more:

Iraq’s crisis: Don’t forget the 2003 U.S. invasion

U.S., Britain’s ‘special relationship’ endures but with less vigor

U.S. military ties with Britain are sheltered from Brexit storm, officials say

Today’s coverage from Post correspondents around the world