Blair woos the MTV kids - and wins over a Swede with anthrax in his spinach

For Tony Blair, it was a question for which no amount of grilling from Jeremy Paxman or briefing from Alastair Campbell could have prepared him: "I am able to produce anthrax in my bath because I've studied up on it. I have anthrax in my spinach in my summer cottage. Why don't you bomb Sweden?"

During the countless hours that the Prime Minister has spent discussing the possibility of war in Iraq he was never asked that one. He paused for a moment, clearly taken aback, but swiftly recovered himself: "Because the Swedes haven't killed thousands of people."

The question from Niklas Ergarvt, from Lund in Sweden, formed part of an hour-long debate during which Mr Blair placed himself under the interrogation of 40 young people from 24 countries. The results will be screened around the world by MTV from tonight.

As the Prime Minister settled himself into a blue armchair in a television studio in north-west London, the programme's presenter Trevor Nelson announced to his audience a world exclusive with the lead singer of a band called Ugly Rumours, a reference to Mr Blair's musical exertions at Oxford University.

But that was as rock and roll as it got. Rather than being roasted by a gang of angry youths from the streets, Mr Blair could have been back at his alma mater, appearing before the Oxford Union.

A succession of soberly dressed questioners in their early 20s demanded further explanation of Mr Blair's apparent determination on a course of conflict.

The Prime Minister told the audience: "Getting rid of Saddam would be an act of humanity."

Faced with results of an MTV poll showing that 83 per cent of viewers thought that Iraqi oil was the motivation for war, Mr Blair made the audience a promise. "That oil goes into a trust fund – we don't touch it and the Americans don't touch it without UN authority," he said.

With the majority of the audience firmly opposed to military action, the programme makers listed Saddam's crimes in an attempt at balance.

"He regularly uses the following methods of torture: rape by broken bottle, electric shock to the genitals, eye-gouging, acid baths," a voiceover told the global audience.

To the Iraqis among the studio audience, Mr Blair was a figure of hope. "I applaud your courage and your leadership," said one British-based refugee.

Downing Street had jumped at the opportunity to put the Prime Minister before the MTV audience after the debate was suggested three weeks ago. It was Mr Blair's most blatant attempt to win the approval of young people since he invited Noel Gallagher and other Cool Britannia heroes to appear at Number 10 in 1997.

An audience member, Imran Saithna, 24 from Harrow, north-west London, welcomed the Prime Minister's attempts to engage with youth but doubted that opinions had been changed by the exercise. 'I think politicians have a way of taking the energy out of situations,' he said. At one point in the debate, Mr Blair was asked when he was going to switch his attention from trying to convince the UN Security Council of the need for war and "start convincing people on the street''.

The Prime Minister responded: "I'm here. You are not members of the Security Council. I'm trying to have a dialogue with people all the time.''

But the reply came: "It's not really working, is it?"

At least Mr Ergarvt, the man with anthrax in his spinach, had some kind words to say about Mr Blair. "I was very impressed by his ways of turning away different subjects," he concluded.