Sandra Osborne abstained in the Commons vote

Ayr MP Sandra Osborne, Scottish Secretary Helen Liddell's parliamentary aide, has resigned from government.

Mrs Osborne said war should only be conducted with the backing of the United Nations and abstained in Tuesday's Commons vote.

Prime Minister Tony Blair won Commons backing to send UK forces into battle.

Having made those views clear I don't believe I can stay in the government Sandra Osborne MP

In the vote, 217 MPs - as many as 139 of them Labour backbenchers - backed a rebel amendment opposing the government's stance on Iraq, with 396 opposing the motion.

A motion backing the government's position was passed by 412 votes to 149.

Mrs Osborne said the prime minister had worked tirelessly for a second resolution and blamed the French for scuppering its chances.

Cook resigns

Mrs Osborne said: "I have made it clear that I'm unhappy at not having a second resolution from the United Nations, but I do believe that the prime minister has done all that he can to achieve that.

"Having made those views clear I don't believe I can stay in the government."

Mrs Liddell thanked the MP for her work since she took up the role of parliamentary secretary in July 2002.

Earlier Mrs Liddell defended the prime minister's policy on Iraq following the resignation of cabinet colleague Robin Cook.

She said the tide of public opinion was turning in favour of military action in the face of last-minute intransigence from Saddam Hussein and the case for such action had been proved by Mr Blair.

Helen Liddell backed the prime minister

However, Livingston MP Mr Cook repeated his assertion that international agreement on war with Iraq had not been reached and he would vote against the government on the issue in the Commons on Tuesday.

With Saddam Hussein and his family given a 48-hour deadline to quit Iraq by US President George W Bush, the impending conflict further exposed the rift between the pro and anti-war factions in Labour.

In a damaging move, Mr Cook became the most senior party member to break ranks with the leadership.

However, Mrs Liddell said other senior Labour figures remained steadfast.

'Abandoned diplomacy'

She said: "The vast majority of the cabinet remained and are 100% behind the prime minister.

"And you must not assume that just those who resign examine their consciences very closely. The rest of us do so as well."

Mrs Liddell insisted that the public and her Constituency Labour Party in Airdrie and Shotts would back war.

She said: "I have talked to thousands of people on this issue over the past few weeks and I think people are saying we cannot let Saddam Hussein off the hook. I believe public opinion is turning."

Robin Cook resigned from cabinet

Former foreign secretary Mr Cook said he had to follow his conscience and stand down ahead of Tuesday's Commons vote.

Scottish National Party Leader John Swinney said military action was "now inevitable" because Mr Bush and Mr Blair had "abandoned diplomacy in favour of war".