The Bloody Sunday inquiry starts its final phase in Derry today almost six years after it was set up by British Prime Minister Mr Tony Blair in January 1998.
Between 40 and 50 civilian witnesses will give their evidence to the inquiry between today and mid-December, when the formal oral hearings are due to end.
So far 842 witnesses have given evidence to the inquiry into the January 30th, 1972 killings by paratroopers of 13 civilians and woundings of 13 other civilians during an anti-internment march in the Bogside area of Derry.
The inquiry started in Derry's Guildhall on March 27th, 2000, two years after it was announced by Mr Blair in the House of Commons.
The opening statement to the inquiry by its counsel, Mr Christopher Clarke, lasted 42 days, the longest opening statement in international judicial history.
Mr Clarke's first two sentences were: "On Sunday 30th January, 1972, 13 identified people are known to have died and a similar number to have been wounded, probably in the course of no more than 30 minutes, on the streets of this city not far from where I now stand. It seems clear that most, if not all of the casualties, were the result of army gunfire."
The first witness to give evidence to the inquiry was Mr Daniel Gerard Porter, on November 28th, 2000. Today Sunday Times journalists Mr Liam Clarke and Ms Kathryn Johnson, co-authors of the book From Guns To Government , will become the 843rd and 844th witnesses respectively.
The hearings moved from the Guildhall in Derry to the Central Hall in London in September of last year where it heard evidence from 270 political and military witnesses, among them former British prime minister Sir Edward Heath and Gen Sir Michael Jackson, chief of the general staff.
Among those due to give evidence over the next six weeks are Sinn Féin's Mr Martin McGuinness, who was second in command of the Provisional IRA in Derry on Bloody Sunday and several other former members of both the Provisional and Official IRA.
Mr McGuinness's evidence is scheduled to start next Wednesday and is expected to take up to two days to complete.
So far the inquiry has cost just over £120 million and it's believed that the final figure will be in the region of £150 million. The most recent figure of the fees paid to lawyers is £62.5 million. The inquiry's website has received 8.5 million hits since it was set up in January 1998 and so far 13 million words have been spoken at the inquiry's hearings, which have lasted 387 days.
The original Widgery Inquiry into the Bloody Sunday killings lasted just 20 days.