Lord Laird of Artigarvan has previously claimed the Republic's media is infiltrated by the IRA and has demanded that two senior RTE officials explain their "extreme republican backgrounds".

He took part in the RTE discussion on the 1916 commemoration on 3 March. Fellow guests included author and historian Tim Pat Coogan, defence minister Willie O'Dea and writer Fintan O'Toole.

"I was delighted to be asked on the programme. I'll take my argument anywhere and I always relish the challenge of addressing a new audience, " Laird told the Sunday Tribune.

"It was arranged with RTE that I flew from London to Dublin on Friday evening. No one else was privy to those arrangements except RTE. On Thursday, I was phoned by the British embassy in Dublin and told my travel details were in the hands of Sinn Fein. I was warned that Sinn Fein was considering a picket at Dublin airport or at RTE studios."

Laird spoke to police but "never considered pulling out of the programme as I wouldn't give in to Sinn Fein. The pickets didn't materialise but I'm not happy about what happened. I was treated very courteously by RTE but I want to find out how this breach in security happened."

An RTE spokesman said the Late Late Show was aware of Laird's concerns on the night, but not of any leak of his travel arrangements.