The hunt for a new top team to revive the ailing Scottish Labour Party has officially started, with nominations now open for the posts of leader and deputy leader north of the border.

With just over six months to go until the Westminster elections - in which a poll has predicted Labour could win as few as four Scottish seats - Ed Miliband needs the party's fortunes to improve if he is going to become the next prime minister.

Three candidates have already put themselves forward to succeed Johann Lamont - who quit suddenly last week - as Scottish Labour leader.

MP Jim Murphy, a former Scottish secretary and the current shadow international development secretary, has already emerged as the favourite for the job.

But he faces competition from Holyrood, with MSPs Neil Findlay and Sarah Boyack both wanting the post.

There are currently no candidates for the post of deputy leader, a vacancy which emerged after Anas Sarwar announced his resignation from the position at Scottish Labour's gala dinner in Glasgow last night.

One potential candidate, North East Scotland MSP Jenny Marra, has ruled herself out while another possible contender - Lothian MSP Kezia Dugdale - has yet to say if she will stand, although there has been speculation that she could run on a joint ticket with Mr Murphy.

Mr Sarwar will stay on as Scottish Labour's interim leader until the new leader and deputy are announced on December 13.

His announcement last night that he is stepping down as deputy leader comes after a dismal week for the party north of the border.

Ms Lamont resigned last Friday, hitting out at colleagues in Westminster for treating the party in Scotland like a "branch office".

Yesterday an Ipsos MORI poll for STV News found that 52% of Scots would vote for the SNP if there was a Westminster election tomorrow while only 23% would vote Labour, suggesting the SNP could secure 54 Scottish seats in the Commons, with Labour reduced from 40 to four.

Meanwhile, a YouGov poll for The Times put the SNP on 43%, which would give them 47 seats, with Labour on 27%, which would slash their Scottish seats by a quarter to 10.

Mr Sarwar's resignation came just hours after fellow MP Mr Murphy declared he was standing for leader - and added that having an MSP deputy would be "compulsory" if he succeeds.

Mr Miliband acknowledged that Labour has had a "tough week" but said its general election success and devolution referendum in 1997, and the success of Labour-led Better Together in September, demonstrates that the party can win.

In a speech to the gala dinner, Mr Miliband said he was looking forward to "working shoulder to shoulder with whoever the party in Scotland elects as leader" to win next May's UK election.

"We face a tough fight but no tougher than the fights we have faced in the past," he said.

"In the next six months I know the Scottish Labour Party will fight every hour and every day to deliver the changes the working people of Scotland need to improve their lives."

Mr Sarwar said it was "in the best interest of the Scottish Labour Party" if he handed the leadership over to a new team on December 13.

"While remaining in post until that time as interim leader, I think it is also right that we have a concurrent leadership and deputy leadership election."

Ms Boyack told BBC Radio 4's Today programme: "I think we have a huge challenge in front of us and our task is to get moving, to get talking to people who voted in record numbers in the recent independence referendum and to persuade them that Scottish Labour will represent them, will be on their side.

"We have got to reconnect with people. We are not doing as well as we need to.

"We need to make sure we build an effective party, we need to devolve how the party works in Scotland and we need to make sure we have a clear programme, a clear plan of action of how we would take the country forward."

Mr Findlay told Today: "It's certainly not our finest hour at the moment, that's for sure. I think we are in a very worrying situation that requires a political response.

"It's about addressing the basic things that people are concerned about, all the things that came out through the referendum.

"People are talking about employment and the need to get people back to work, they are talking about people working for poverty pay in appalling conditions, they are looking for fairness at work, they are talking about the NHS and they are talking about public services that are being decimated."

He added: "People were raising throughout the referendum the issue of social justice and social justice-related issues like employment and the living wage.

"These are the things that will get us back connected with the voters and Labour has to have an offer that is radical and connects with people."