Prime Minister David Cameron is to judge a competition launched by the Anne Frank Trust UK for young people to say how they would make Britain a better place.

The “Thirteen in 13” project will ask British teenagers to write a 250-word online letter to Mr Cameron, giving their ideas for improving the country.

The trust launched the contest to reflect the fact that Anne Frank received her diary as a present on her 13th birthday.

At the end of the competition, a panel, including Anne Frank’s step-sister Eva Schloss, will select the top 13 letters, with Mr Cameron writing an open response to the winners to be published in the Times in July.

He said: “I am delighted to support the campaign to encourage young people to write about what they want to see in the world.”

Gillian Walnes, co-founder and executive director of the trust, said: “I am encouraging as many Jewish schools and children as possible to take part in the campaign — the winner could hopefully be from the Jewish community.”