Prime Minister Gordon Brown is facing a political coup as rebel Labour MPs plot to oust him from Number 10.

Meanwhile, Mr Brown's friend Sir Alan Sugar, who is a member of the Business Council for Britain - has been spotted at Downing Street prompting talk that he could be set for a job amid an imminent reshuffle.

Whether he shouted his famous catchphrase, "You're fired", at the PM is, however, unknown.

Mr Brown's authority is on the line after the emergence of an email urging him to quit was circulated among his own backbenchers. It followed Hazel Blears' surprise resignation as Communities Secretary, which came hard on the heels of Home Secretary Jacqui Smith and two other ministers who are to leave the Government.

The email reads: "Over the last 12 years in government, and before, you have made an enormous contribution to this country and to the Labour Party, and this is very widely acknowledged.

"However we are writing now because we believe that in the current political situation, you can best serve the Labour Party and the country by stepping down as party leader and prime minister, and so allowing the party to choose a new leader to take us into the next General Election."

No MPs have so far broken cover to claim ownership of, or support for, the email. Under party rules, 71 of Labour's 351 MPs are needed to mount a leadership challenge to an incumbent.

The email apparently states that its ringleaders will not publish a list of names until it reaches 50 in number, but they hope to secure "significantly more".

It also pays tribute to Mr Brown's "significant contribution" to the country and the Labour Party.

Ms Blears offered no praise for the Prime Minister, who singled out her expenses claims for criticism amid recent controversy over her failure to pay capital gains tax.

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