General Election 2015: 10-year-old girl asks David Cameron the best question of the campaign but he still fails to give an answer

David Cameron has rarely come unstuck on the campaign trail so far, batting away questions with his usual smooth, predictable and dull responses.

And when he faced an audience of schoolchildren in Bolton for BBC's Newsround show, he must have been predicting an easy ride.

But he ended up being asked the toughest question of the election campaign so far, as he admitted himself.

“If you could pick one politician apart from yourself to win who would it be and why?” asked Reema, a ten-year-old girl from Salford, Greater Manchester.

The Prime Minister was stumped and - like too many times during this campaign - failed to come up with an answer.

“Wow. If I could pick politician? Would they have to be living or dead?

“If I thought someone else should win the election I would not be standing myself, so I can’t really answer the question about who else I would like to win.

“There are lots of candidates around the country I am very enthusiastic about.

“I am afraid it is too difficult to say I would like someone else to win other than me or I wouldn’t be here, and I am quite keen on winning."

Despite not giving an answer, he did give the schoolgirl an A* for the question.

He said: “Top question – it is the best one I have been asked all election campaign.”