An anti-war campaigner tried to make a citizen's arrest on Tony Blair as he signed books

An anti-war campaigner has attempted to make a citizen's arrest on former British prime minister Tony Blair over alleged war crimes.

Activist Kate O'Sullivan managed to get through tight security to confront Mr Blair as he held a book signing in Dublin.

"I went up to him and I said 'Mr Blair, I'm here to make a citizen's arrest for the war crimes that you've committed'," she said.

"Immediately five security people grabbed me, started dragging me off.

"I cried out there was half a million people dead in Iraq, how can you live with yourself, you've committed war crimes."

Ms O'Sullivan, 24, from Cork, said she queued for 90 minutes and went through airport style security - handing in all her belongings and going through a metal detector - before she attempted to arrest Mr Blair.

"He was really blase about it, it was nothing but awkward for him," she continued.

"That's insane. If someone is crying out you murdered half a million people your reaction shouldn't be blase. He looked annoyed. He didn't say anything, he just signed the book, he looked down and then looked at security."

Ms O'Sullivan, a member of the Irish Palestine Solidarity Movement, was detained for almost half an hour before she was cautioned by gardai.

She accused Mr Blair of making money from war crimes. "He is a war criminal and he has pretty much gotten away with it," she added. "He's making money going around the world. He's a war criminal."

PA Media