British Prime Minister Tony Blair appeared at celebrations for the 50th anniversary of Queen Elizabeth's rule in 2002 despite police warning of a threat to kill him, according to a BBC documentary.
Former London police chief John Stevens said in the documentary, to be screened on Tuesday, that what police believed was a "credible" assassination threat was made against Mr Blair at the time of the queen's Golden Jubilee five years ago.
The documentary did not say who made the threat but said Mr Blair's support for President Bush and for the "war on terror" had made Mr Blair a target.
Police were concerned about whether Mr Blair should attend a huge London street party held in honour of the queen in June 2002 and Mr Stevens went to talk to Mr Blair about it.
"He was absolutely determined he was going to go ahead with the public appearances and said to me: 'Oh John, I'm quite sure you'll do everything that's necessary as you have done in the past'," Mr Stevens said, according to a transcript of the documentary.
Mr Stevens said Mr Blair was "probably more optimistic" than he was about the police's ability to protect the prime minister.
"So we went ahead with it and as a result we had a lot of police officers around, a lot of marksmen around the actual vicinity, and I remember sitting with him . . . outside Buckingham Palace where . . . we knew we were extremely vulnerable," he said.