A coalition of senior MPs is to table a motion in the House of Commons calling for a "special committee" to look at changing the electoral system.

The call for a parliamentary inquiry to examine the case for voting reform is a direct challenge to Tony Blair on his mandate to govern without a majority of votes as MPs

At his monthly press conference on Thursday the prime minister was asked whether he had a real mandate to govern in England after the Tories secured more votes than Labour in England in last week's election.

He denied that this raised questions about his authority. "In the end, I think you have one class of MP," he said.