Forget Evan Davis, Andrew Neil or Emily Maitlis, David Cameron has faced his toughest BBC interview yet - from a group of young listeners on Radio 1's Live Lounge.

The prime minister took part in a half hour Q&A with a group of young people where he was relentlessly grilled on issues like the LGBT community, the SNP and the "tampon tax".

Presenter Chris Smith even offered Mr Cameron a £1,000 wager that he would not win a majority at the election (an offer he did not decide to take him up on).

However, his biggest problem came with the living wage. After a particularly heated exchange with April from West London, in which the prime minister was repeatedly pressed on whether he would like to see a living wage introduced and if he could live off £6.50 an hour (the minimum wage), he became really unstuck when Smith asked him about one crucial piece of information.

Here's a brief transcript:

You do know how much the living wage is don't you?

Chris Smith

Well it depends on different parts of the country. And we pay, and for instance...

David Cameron

Outside London then?

Chris Smith

For instance, in Downing Street we pay the living wage and I want more parts of government to do so...

David Cameron

Sorry, do you know how much the living wage is?

Chris Smith

Well in... it's different in different parts of the country.

David Cameron

Ok, how much in London?

Chris Smith

I don't have the figures in my head. But, it's different to the living wage...

David Cameron