SCOTTISH Labour is planning to fight the next Holyrood election on a pledge to raise income tax for the wealthiest, in a move that will put pressure on the SNP to follow suit.

The party's new leader, Kezia Dugdale, signalled the move in a speech in Edinburgh when she told supporters a more equal society could not be achieved without redistribution.

Holyrood will become responsible for setting income tax rates and bands during the lifetime of the next parliament as part of the wide-ranging package of new powers agreed by the Smith Commission.

Ms Dugdale said the transfer of income tax meant there would be "no more excuses for the perpetuation of inequality and injustice".

She did not mention the SNP by name during her speech at Edinburgh College but, in an indirect challenge to the Nationalists, said: "Everyone in Scottish politics will have to stop complaining about what we can’t do and start talking about what we can do.

"If those in positions of power genuinely believe that something is wrong, if they really want to change things, then they can.

"The only thing stopping them will be a lack of political will.

"No more easy rhetoric, only the hard choices that come with power."

She added: "The new tax and welfare powers mean that those who position themselves on the left will have to put their money where their mouth is.

"Power means that left wing posturing will have to be replaced by socialist policy.

"If you believe in the redistribution of power and wealth, as I do, you’d better get ready to say how you’ll achieve it."

Ms Dugdale said she supported existing universal services, which include free prescriptions and bus travel for pensioners, but added: "Let’s be clear we cannot have a more equal society without redistribution.

"We cannot fund public services unless the wealthy, as well as the rest of us, pay a fair share."

She said her position would pose a challenge to a "new  establishment" centred on the SNP-led government and based on the notion "that shared identity means shared interest".

She also predicted she would face "personal attacks that have become an unfortunate but unavoidable fact of political life in Scotland".

Holyrood will assume limited control over income tax next year when the parliament becomes responsible for about the half the tax raised in Scotland.

Finance Secretary John Swinney will set the Scottish Rate of Income Tax (SRIT) for the first time next month, to be applied in financial year starting in April.

However, any increase to the upper rate would have to be mirrored by a rise in the basic rate, leading to speculation Mr Swinney will not depart from existing UK rates.

The switch to full control over income tax rates and bands - which could be devolved as early as 2018 - will force all the parties to set out their tax plans before next May's Holyrood elections.

Ruth Davidson, the Scottish Tory leader, has already promised to fight the election on  a promise to cut income tax by at least 1p in the pound.

A Scottish Labour insider said: "Kezia is simply re-iterating what we have said before.

"The party's position is to use the new powers to re-establish a 50 top rate of income tax and use the revenue to close the attainment gap in schools between children from better and less well off backgrounds."

Before the General Election, Jim Murphy, the previous Scottish Labour leader, said raising the top rate of income tax from 45p to 50p for the 16,000 Scots earning over £150,000 would raise up to £250million.

The SNP backed the proposal a few weeks before the election, after it had apparently been ruled out by former leader Alex Salmond.

SNP MSP Sandra White said: “We have been clear we support the restoration of the 50p tax rate for those earning over £150,000 - along with a bankers' tax and mansion tax - to ensure those who can afford to contribute more to society do so.

"If Kezia Dugdale is serious about reducing inequality, she must commit to working with the SNP to deliver our socially progressive policies that will help make Scotland a better country."