Gerry Adams has said "very few tears" would have been shed if the Brighton bombing killed Margaret Thatcher.
The IRA attack on the Conservative Party conference in 1984 killed five people. They included an MP, the party chairman and three wives of Tory MPs.
Thirty-one others were injured, while the former British prime minister escaped uninjured.
The former Sinn Féin president was asked by The Rest is Politics podcast if he would have been happy if Mrs Thatcher died that day.
Mr Adams said: “Happiness or happy is not a term I would use. The fact is, there was a war. Margaret Thatcher was notorious, not just for her presiding over the deaths of the hunger strikers, which could have been easily resolved, by very simple improvements in the prison regime.
"She was up front, and she was being the 'Iron Lady' and she was masquerading as somebody who was indomitable and so on and so forth. So, there would be very few tears shed for Margaret Thatcher or in republican Ireland or in many villages in Wales... or in working class neighbourhoods in Scotland or in England itself."
The Rest Is Politics is presented by author Alastair Campbell and former Conservative politician Rory Stewart.
When Mr Stewart, who was previously a soldier in the British Army, challenged Mr Adams, he replied: “I never went to war. You came to me, you know. You came in, in khaki and tanks. I think including the deaths of British soldiers and RUC officers, all those deaths are to be regretted.
“It’s a regrettable part of our history... and, clearly for civilians, for them to be killed, it doesn’t matter if it was an accident or not. That’s even more regrettable, and thankfully we’re now out of all that... and we need to learn the lessons of it.”