A Conservative MP has used parliamentary privilege to name a man wanted for questioning about the Omagh bombing.
Twenty nine people died in the Real IRA attack
It is claimed the man passed a warning to the Gardai before the attack was carried out.
During Northern Ireland Question Time, Tewkesbury MP Laurence Robertson claimed the Irish authorities had refused to hand the man over to police in Northern Ireland.
Twenty-nine men, women and children died and hundreds were injured in the car bomb attack in the County Tyrone town on 15 August 1998.
Mr Robertson said in the Commons on Wednesday: "Can you explain why the Irish Republic refused to hand over Paddy Dixon who was wanted in connection with questioning with the Omagh bombing?
"Can you also tell me if Paddy Dixon has been relocated to the United Kingdom, because recently he was stopped in Cardiff by the authorities?
"He was found to have a great deal of cash on him. Why were the Police Service of Northern Ireland not alerted to the fact that he was in Great Britain?"
Northern Ireland Office Minister Ian Pearson replied: "There is a good strong
level of co-operation between the Police Service of Northern Ireland and the
Garda Siochana on a wide level of issues, certainly including dealing with
paramilitarities and dealing with the issue of organised criminal activity.
"As far as the individual concerned that you mentioned, I will look into that
issue and get back to you."
The Omagh bomb was the single worst atrocity in 30 years of violence in Northern Ireland.