John McDonnell has apologised for praising the IRA and claimed he did "everything I possibly could to secure the peace process in Northern Ireland".
The Shadow Chancellor caused controversy when he called for former IRA militants to be "honoured" during an event to remember the death of hunger striker Bobby Sands.
Speaking in 2003 he said: "It’s about time we started honouring those people involved in the armed struggle. It was the bombs and bullets and sacrifice made by the likes of Bobby Sands that brought Britain to the negotiating table.
"The peace we have now is due to the action of the IRA. Because of the bravery of the IRA and people like Bobby Sands, we now have a peace process."
Police forensic officers working on the remains of the IRA car which housed the Hyde Park car bomb
His comments were condemned and he was forced to apologise on the BBC’s Newsnight programme and in an article.
Asked again about the remarks at a press conference he said: "I apologise for those words, but I also said no cause is worth an innocent life and I made that explicitly clear. I also did everything I possibly could to secure the peace process in Northern Ireland and at times that was contentious, of course.
"We were trying to talk to people you were condemned for talking to, then we discovered that governments were talking to them anyway.
"So I’ve apologised for my language, but I made it absolutely clear that everything I did was about securing peace and no innocent life lost is worth it."
The shadow chancellor
Asked if he believed the IRA played a key role in bringing about the peace process, Mr McDonnell added: "I think the peace process was as a result of a dialogue that many undertook, and if I contributed in any small way I was pleased to do so. But I apologise for the language that I used. No cause is worth the loss of an innocent life."
The shadow Chancellor was speaking at an event to highlight changes in the Conservative manifesto which will affect pensioners across the country.
He warned removing winter fuel allowance from wealthy older people, scrapping the triple lock and a new plan for social care would hit pensioners hard and claimed Labour would protect them.
Mr McDonnell defended winter fuel payments being handed to well-off movie stars and musicians across the country even though they do not need it, adding that the universality of the benefit means it gets to those who need it most.
The Labour politician, who is 65, also admitted claiming his winter fuel allowance, saying: "With regard to the winter fuel allowance, I spend it on winter fuel.
"But the issue there overall is that I’m on an MPs salary and I get taxed as a result of that it will contribute to the overall exchequer and that’s the fairest way of doing it.
"I do not want means testing introduced on winter fuel because we know… at least a third do not claim pensioner credit because it’s means tested.
"I think it’s a more efficient way of getting the money to where it is really needed."