Every Labour backbencher was the recipient of a personal letter from the prime minister last night asking them to support the government in tonight's vote.

Members of the cabinet - led by deputy prime minister John Prescott - toured the Commons tearoom yesterday.

"It was an extraordinary sight; ministers and whips outnumbered backbenchers by two to one," one Labour rebel told today's Guardian.

Cherie Blair joined the Downing Street operation last night by phoning wavering MPs to ask them to support the prime minister.

She is reported to have focused on women MPs who have worked closely with her on women's issues, reportedly asking them if they still supported her husband.