DEMANDS for a “popular front” to challenge the Tories at the next general election grew louder yesterday as leading figures from four parties met to discuss the idea.

Labour’s Clive Lewis, Green leadership candidate Caroline Lucas, former Lib Dem minister Vince Cable and SNP MP Tommy Shepherd began to hammer out the details for a pact at a meeting of 1,000 activists in London.

The cross-party Compass think tank, which organised the meeting, has long campaigned for an electoral alliance but the prospect of a snap general election later this year — and the attempted coup in the Labour Party — has forced the issue.