Tony Blair yesterday tried to convince scores of Oxford teenagers of the importance of science - but it seems they weren't on his wavelength.

The Prime Minister returned to the county to speak to about 300 scientists, industry figures and students at Oxfordshire Community Churches' base, The King's Centre, in Oxford's Osney Mead, in the fourth of a series of speeches about the key challenges facing Britain.

His speech followed a visit to see the building of the Diamond Light Source at the Harwell Science and Business Campus on Thursday.

He spoke to pupils from Cheney, Matthew Arnold and Cherwell schools in Oxford about the importance of science in delivering prosperity and said it was crucial young people viewed science as a desirable career.

But sixth formers from Cheney School, in Headington, said the speech focused too heavily on the money-making aspect of science, instead of its humanitarian uses.

Elliot Carter, 17, said: "I hated all the stuff about business. He said we should follow the needs of businesses, when there are big issues, such as Aids, which I consider more relevant.

"I don't think emphasising the business element is what's going to encourage people to go into science."

Rita Oldenbourg, also 17, said: "If it all becomes about manufacturing and processing and business science, I wouldn't be encouraged to do it."

Annie Rayner, 17, added: "I think what he was saying about encouraging more scientists is great, because we obviously need more, but the business side just isn't particularly inspiring."

Mr Blair admitted science had not been his strongest subject at school and described himself as something of a 'refusenik', adding: "I felt I didn't understand it and it didn't understand me.

"I've become determined, if I can say it in these surroundings, evangelical, that the attitude I now recognise from my youth shouldn't be the attitude of young people today.

"For Britain, science will be as important to our economic future as stability."