Scotland Secretary Jim Murphy and Labour's leader at Holyrood Iain Gray both hit out during speeches to the party's annual conference in Brighton.

Mr Murphy described David Cameron as "the most superficial leader in modern history" and said Tory candidates in Scotland were "probably the most hard-line in living memory".

Meanwhile Mr Gray said the Tories had been "nuzzling" up to the SNP - which he described as a "campaign", not a government.

Speaking to delegates on a day labelled "ambitious Britain" by conference organisers, Mr Murphy said there would be a "big choice" over the next year.

"Labour government or Tory government; Gordon Brown or David Cameron; Gordon's experience or the most superficial Tory leader in modern history.

"And David Cameron wants to make the Tories a one nation party again - but that nation isn't Scotland."

He said Mr Cameron was a threat to Scotland's families and economy, adding: "The Scottish Tory candidates are probably the most hard-line in living memory.

"They think the only problem with the 1980s was that their party didn't go far enough in cutting back the welfare state and they can't wait to finish the job."

Pledging that Labour would protect frontline services while reducing costs, Mr Murphy warned that the Tories were planning "savage cuts" that would put the economic recovery at risk.

And he added: "They believe in small government, in the politics of sink or swim and in the politics of you're on your own. Today's Scottish Tory candidates are Mrs Thatcher's grandchildren.

"In Scotland they are hated by many for their past and distrusted by most because of their present.

"The Tories still don't get Scotland. But Scotland gets them - and doesn't want them back."

After Mr Murphy had savaged the Tories in his speech, Mr Gray went on the offensive against the SNP.

He said Scottish First Minister Alex Salmond had "no mandate, no majority, and no shame", adding: "Alex Salmond is not taking my country forward - he is dragging it back."

The SNP would prefer a Tory government, Mr Gray claimed, because it would bring unemployment and social division that would help their push for Scottish independence.

"The SNP are not a government, they are a campaign," Mr Gray said.

"The day may well come when the people of Scotland want a referendum to settle their constitutional future once and for all. But not now, in the midst of a recession. And not on a question rigged by the SNP."

And issuing a rallying cry to delegates, Mr Gray said: "We must fight, fight and fight again for the future we want to see.

"Together we will defeat those whose sole creed is self interest, whose sole purpose is division whose sole principle is expediency. Whether they are Tories, or Nationalists."