When John Chilcot appears before television cameras on Wednesday morning, it will have been 2,578 days, or just over seven years, since the retired civil servant was announced as the head of an inquiry into Britain’s involvement in the U.S.-led Iraq war.

The families, many of whom will be in the Queen Elizabeth II Centre in central London listening to Chilcot disclose his findings, have been waiting for some measure of accountability since the invasion to topple Saddam Hussein’s regime.

They are the relatives of 179 British soldiers who died in action between March 2003 and April 2009, when the last U.K. troops were withdrawn from Iraq. Nearly 50 were killed by roadside bombs after the initial combat mission. The number of Iraqi deaths over the same period is counted in tens of thousands.

The Chilcot report -- or, to use its official name, the Iraq Inquiry -- was announced shortly after the 2009 withdrawal by then Prime Minister Gordon Brown as an “objective and non-partisan” review of the conflict.

“The objective is to learn the lessons from the events surrounding the conflict,” Brown told the House of Commons on June 15, 2009.

“The Iraq Inquiry will look at the run-up to conflict, the conflict itself and the reconstruction, so that we can learn lessons in each and every area.”

Chilcot and his team would have access to all U.K. government papers and the ability to call any witnesses, Brown said.

What followed was one of the longest-lasting and -- at a cost of £10 million ($13 million) -- most expensive inquiries in British history. The final document is estimated to contain 2.6 million words and hard copies will come in 13 volumes, although it will also be made available online.

More than 150 witnesses were called to give evidence. Tony Blair, who led Britain into the war and whose career has come to be widely associated with it, was called twice.