SCOTTISH Labour will seek to force through key parts of its manifesto from the opposition benches at Holyrood if Ed Miliband becomes Prime Minister after May 7.

The party's MSPs will demand a series of votes in a bid to push through election pledges including 1,000 extra nurses for the Scottish NHS, an additional 500 GPs and a £200million fund to improve cancer treatment.

Party leader Jim Murphy said he wanted to hold the SNP's "feet to the fire" over his plans - before next year's Holyrood election.

Challenging SNP leader and First Minister Nicola Sturgeon to back Labour's policy platform, he warned: "Vote against it if you dare."

The move came as the Conservatives accused the SNP of threatening to "gridlock" a Labour government at Westminster if it did not get its way.

Deputy leader Stewart Hosie said his party would be prepared to vote against legislation put forward by a minority administration.

Some Labour figures believe the SNP would struggle to oppose a Labour government for fear of accusations they are backing the Conservatives.

But Mr Hosie said that if there was no deal with Labour after May, his party's MPs would able to vote against "any bit of legislation they wanted", including those that give ministers the authority they need to spend money.

The Tories accused the SNP of threatening to logjam parliament and planning to hold the UK to ransom.

Ahead of a speech to the Scottish Trade Union Annual Congress today Labour leader Ed Miliband hit out at the SNP.

He said Ms Sturgeon was asking people to gamble on getting rid of a Tory government saying "the only way to guarantee getting rid of a Tory government is to vote Labour€Å½."

But one of his own frontbenchers appeared to break ranks to admit the party may not get an overall majority in the election.

Shadow minister Angela Eagle said that at that stage her party would "speak to any party" in the Commons to build a majority for a Queen's Speech, to set out its legislative programme.

The First Minister will today unveil the SNP's General Election manifesto, which the party says will deliver an extra £2bn for the Scottish NHS and provide a blueprint for how it can work with Labour to change the UK for the better.

Scottish Labour unveiled its manifesto last Friday at a rally in the East End of Glasgow.

Many of the pledges are in devolved areas and would have to be delivered by a Scottish government.

Mr Murphy said: "If we win in May that gives us a source of funding.

"It gives us access to £800million of additional resource from our mansion tax, bankers bonus tax and tobacco tax.

"We will then submit a series of motions to the Scottish Parliament, asking the Scottish Parliament to implement Labour's devolved manifesto.

"The idea that you have to wait until 2016 to implement the manifesto is not true.

"We can start to implement Labour's manifesto in advance of the 2016 election and dare the other parties to vote it down."

Shadow chancellor Ed Balls has promised a post-election Budget to introduce a mansion tax those living in £2million-plus homes, a one-off tax on bankers' bonuses and a levy on tobacco firms.

Labour says the Scottish Government will receive an additional £800million in the current financial year as its share of the new UK taxes.

Mr Murphy's strategy will draw clear dividing lines between his party and the SNP if Ms Sturgeon's government reject Labour's plans for spending the money in favour of other priorities.

The SNP's response is likely to set the tone for the Holyrood election battle, which early opinion polls suggest will result in a third successive Nationalist administration.

Mr Murphy said Labour had produced a "radical manifesto" for Scotland based on "radical tax plans" across the whole UK.

"We will hold the other parties' feet to the fire on their quasi-radical credentials," he said.

As well as extra doctors, nurses and cancer funding, to be delivered by 2020, Scottish Labour has set out plans for a £200million mental health fund, also to be paid for from the mansion tax.

Mr Murphy has earmarked revenue from the bankers' bonus tax to create job and training opportunities for young people out of work for more than a year.

Changes to pension tax relief would pay for free bus travel for apprentices, increase study bursaries to £1000 and provide a "future fund" giving 18- and 19-year-olds not at university a one off lump sum of £1600.