Scottish Labour leadership candidate Jim Murphy has called on his party to agree to the full devolution of income tax.

Mr Murphy also set out plans to introduce a 50p top rate of tax for the wealthiest earners in Scotland - those earning over £150,000 - during a speech in Glasgow.

The MP is facing MSPs Sarah Boyack and Neil Findlay in the battle to become the new leader of Scottish Labour.

Mr Findlay and Ms Boyack also back plans for a 50p top rate of tax, which Ed Miliband has pledged to reintroduce if Labour returns to power at Westminster.

Both MSPs have stated that when it comes to income tax, it must be ensured that Scotland will be not be worse-off as a consequence of any changes.

Tax is one of the main areas that the Smith Commission on further devolution - due to report on Thursday - has been considering.

Scottish Labour has officially backed the devolution of some, but not all income tax, while former prime minister Gordon Brown described full powers over the tax as a "Tory trap".

Mr Murphy told supporters at an event at Mitchell Library in Glasgow: "Even before the Smith Commission reports, we should agree to the full devolution of income tax to Scotland, if that is what emerges."

Mr Murphy emphasised the "clear connection between the raising of taxes and the spending of revenues which is missing at present".

"This will result in there being no hiding place for those who want to talk about radical politics but then fail to deliver them," he said.

Announcing his plans for a 50p rate, he said: "Labour has created the opportunity to have a more progressive tax system in Scotland than in the rest of the United Kingdom.

"We will set out in more detail in the coming months exactly how we will use the revenues this will generate but I want to prioritise creating a more prosperous Scotland by supporting small businesses at the same time as fighting poverty."

Mr Findlay said: "Any devolution of taxes must ensure that we secure a good deal for Scotland. But, let's be clear, constitutional change does not equal political change.

"On tax, I believe in the principle of progressive taxation where the people with broadest shoulder bear a heavier burden to help the poorest. It will be that principal that will guide my thinking on taxation.

"I am also committed to the proposals by Ed Milliband for a 50p and 10p tax rate, a UK-wide bankers bonus tax and a mansion tax on the sale of properties above £2 million.

"I will use existing and new powers, whatever they turn out to be, to prioritise tackling Scotland's deep-seated problems."

Ms Boyack said: "I'm not going to pre-empt the Smith Commission. If Scotland is to get the full devolution of income tax, and that has not been confirmed, I'd want a cast-iron guarantee from Lord Smith that Scotland will be no worse off.

"I've also been clear that as leader I would support the implementation of a 50p rate for earners above £150,000.

"This policy is already supported by Labour at a UK level and must be our ambition for the Scottish Parliament too."

SNP MSP Stewart Maxwell said: "Voices across civic Scotland have already backed the devolution of extensive powers over tax and welfare, and people in Scotland rightly expect to see a broad range of taxation powers transferred beyond income tax.

"If Labour have now caught up on this one aspect, having offered even less than the Tories, I hope that they will back the calls by many independent organisations in Scotland for other tax and welfare powers to be devolved, such as the minimum wage."

Conservative finance spokesman Gavin Brown said: "Our priority has to be growing the economy, creating jobs and helping Scotland's businesses flourish.

"The very last thing we need is a 50p tax rate which would send a terrible signal to entrepreneurs and those who want to invest here."