Suggestions that Labour could enter a coalition with the Liberal Democrats after next year's general election have been dismissed as "nonsense" by the man in charge of Labour's election strategy.

Douglas Alexander, the chair of Labour's general election strategy, said instead his party should hold the Lib Dems to account for their role in implementing policies such as welfare reform and tuition fees hikes.

He insisted that next year's election was "quintessentially winnable" for Labour, as he said the "defining question" of the campaign would be the rising cost of living.

Mr Alexander said Labour had a "genuine opportunity to build momentum" for the election from this September's referendum on Scottish independence.

He said that after that his party could "advance our core arguments about the Liberal Democrats and others at the time of the general election".

He continued: " The Liberal Democrats want to pretend that they are the internal opposition to the Conservatives - they're not the internal opposition, they are the enablers of the Conservatives. The reason David Cameron is sitting in Downing Street is because Nick Clegg is sitting next to him at the cabinet table.

"It was Nick Clegg, Malcolm Bruce, Robert Smith, Danny Alexander, all the rest of them, they voted for the bedroom tax, voted to triple tuition fees, and have got it wrong on the economy month after month after month. We need to hold them to account for that.

"In that sense anybody who suggests we should try and have a coalition with them, it's nonsense.

"We are working and planning for a majority Labour government. We will deliver a majority Labour government."

Mr Alexander, who was speaking at at the Scottish Labour conference in Perth, said Labour's defeat at the 2010 general election came in the wake of the expenses scandal at Westminster and the "worst economic crisis for 60 years".

But he said: " Even in those circumstances David Cameron couldn't win a majority Conservative Government. The Conservatives haven't managed a majority in a Westminster election now for more than 20 years."

He claimed the Tories were " in wholesale retreat across the United Kingdom", saying: " It's not just that they have one Tory MP in Scotland, they don't have a single elected councillor in the great cities of Liverpool, Manchester, Sheffield or Newcastle.

"Under David Cameron's leadership the membership of the Conservative Party has more than halved to under 100,000."

He told party activists: "W hen we do face that general election in 2015 I want you to understand it's not just that we are up against a bad government that deserves to lose, but we as the Labour Party will be contesting a quintessentially winnable general election."

Mr Alexander went on to say the "cost of living crisis being experienced by people the length and breadth of the United Kingdom" would be the " beating heart of our campaign".

He said: " This is going to be the first Parliament in decades where British people are worse off at the end of the Parliament than at the beginning, more than £1,600 worse off for an average family than they were in 2010.

"So that will be the defining question of the general election."