Ken Livingstone has ignored a demand from Tony Blair that he apologise for an allegedly anti-Semitic remark made to a Jewish journalist.

Members of Labour's national executive committee said London's mayor could be disciplined if he did not withdraw comments in which he compared the journalist to a "concentration camp guard".

The prime minister, speaking during a Channel Five programme, said: "A lot of us get angry with journalists from time to time, but in the circumstances in which the journalist was a Jewish journalist, yes, he should apologise. He should apologise and move on."

Meanwhile, members of London's Olympic bid team were grilled by international inspectors yesterday as the row over the mayor threatened to overshadow the bid.

Sir Steve Redgrave said the questions posed by the inspectors were very in depth.

"Some of the bid team came out of the room looking a little bit concerned," he said.

Dame Kelly Holmes added that: "When I heard the questions, I was very pleased I was not in the position of having to answer them."