AV referendum: Vince Cable attacks 'ruthless' Tories over poll defeat

"Some of us never had many illusions about the Conservatives, but they have emerged as ruthless, calculating and thoroughly tribal," Cable said.

"But that doesn't mean to say we can't work with them. I think they have always been that way, but you have to be businesslike and professional and you have to work with people who aren't your natural bedfellows and that is being grownup in politics."

The referendum on changing how Britain elects its MPs was a major concession secured by the Lib Dems when they formed the coalition with the Tories last year. But in Thursday's poll it was rejected by 13,013,123 votes to 6,152,607.