David Cameron makes sex joke during speech at Tory Party Conference

Twitter reacted with horror

David Cameron reacts as he speaks at the annual Conservative Party Conference in Manchester (Reuters)

David Cameron made an unsavoury sex joke in a break from a section in his speech about security.

He began talking about Labour's "economic guru" Richard Murphy before reaching the punchline: "His book is actually called The Joy of Tax. I've got it. I took it home to show Samantha. It's got 64 positions - and none of them work."

Twitter reacted with horror to the quip, calling it "bizarre", "creepy" and "contrived".

The joke was made shortly before Mr Cameron took a swipe at Lord Ashcroft and his book Call Me Dave.

Speaking to delegates in Manchester he said: "That was a great speech yesterday Boris [Johnson], a fabulous speech.

"I was a hooker. And by the way that's a factual statement, not a chapter in Ashcroft's new book."

Lord Ashcroft made several allegations in his unauthorised biography which, according to the Huffington Post, is the top selling book at the Conservative Party Conference.