There will be a huge media spotlight on the Guild Hall in Derry on Tuesday when Sinn Féin's Mr Martin McGuinness gives evidence to the Bloody Sunday Inquiry.
The Mid-Ulster MP is expected to deny allegations that he planned IRA nail bomb attacks on Bloody Sunday and that he fired the first shot of the day.
Mr McGuinness, who in January 1972 was the second in command of the IRA in Derry, will appear as the 854th witness on the 390th day of the inquiry, which to date has cost £120 million.
A team of about six to 10 journalists cover proceedings normally but this is likely to swell to 100 during Tuesday and Wednesday when Mr McGuinness gives his evidence.
Sinn Féin's chief negotiator will be taken by the tribunal counsel, Mr Christopher Clarke QC, through his 113 pages of written statements and will then face cross-examination from various lawyers, including those representing the British soldiers who shot dead 13 civilians that day. A 14th victim died later.
He will have to deal with allegations that he planned a nail bomb attack on Derry city centre commercial premises on Bloody Sunday and that he fired the first shot on the day from a Thompson submachine-gun.
Some of the allegations against him are contained in the book Martin McGuinness: From Guns to Government by journalists Liam Clarke and Kathryn Johnston, who this week gave evidence to the inquiry.
Former IRA and INLA man Mr Paddy Ward, one of the sources for the biography, also alleged to the inquiry that Mr McGuinness had planned to use the Bloody Sunday march as cover for a nail-bomb attack in the commercial centre of Derry.
Mr McGuinness's solicitor, Mr Barra McGrory, has already described these allegations as "a complete and utter fabrication and a tissue of lies", and "pure fantasy".
Mr McGuinness is also expected to repeat that on the day of the march the IRA was instructed to stay away. He is also likely to repeat that he was unarmed at the march.
He has already put on record that he will not provide names or details about IRA members and that his evidence will relate to Bloody Sunday only and relevant events preceding it.
