Miliband and Blair
Labour Party leader Ed Miliband and former Prime Minister Tony BlairReuters

Ed Miliband could become Labour's second most successful leader in modern times despite a "crisis" surrounding his stewardship of the party, according to analysis from IBTimes UK.

A poll from Survation for the Mail on Sunday, which questioned more than 1,000 people, found that Labour (34%) have a five point lead over the Conservatives (29%) ahead of the 2015 General Election next may.

The survey, which put Ukip on 25% and the Liberal Democrats on 6%, means that Miliband's party would gain 99 seats at the General Election and hold a majority of 64, according to Electoral Calculus.

The calculation means Miliband would become Labour's second most successful leader of modern times, based on net number of seats gained at general elections contested.

The claim comes as research from Charles Clarke, a former senior Labour MP, found that Clement Attlee (+225) was the most successful modern leader for Labour, JR Clynes (+85) second and Tony Blair third (+84).

The findings come amid an alleged "leadership crisis" for Miliband, which Ed Balls has called "nonsense".

"I think this is all nonsense, to be honest. I've no idea about any of this," the Shadow Chancellor told BBC News.

"All I know is that everybody in the Labour party, from Miliband down, is focused on tackling the cost of living crisis, building an economy which works for working people, reforming Europe but not walking away, getting tough and fair controls on immigration, saving our national health service – that's what Labour's for.

"It's the Conservative Party which are riven and divided and defecting, left, right and centre. Labour will stay united."

However, a popularity surge for the Scottish National Party north of the border, following the Scottish independence referendum, means that Miliband's party could lose a significant amount of seats in Scotland in May.

An Ipsos MORI poll for STV News found that the SNP climbed to a 29% lead over Labour.

The survey, which questioned more than 1,000 people in October, found that Miliband's party would only win 23% of the Scottish vote, down from the 42% it secured in 2010.

The poll means that the SNP would have a projected 54 seats at Westminster and severely reduce Labour's 41 Scottish MPs.