RUTH Davidson will today open a new chapter for the Scottish Conservatives by backing more tax powers for Holyrood as senior sources make clear the days of the Tories seeking to put the brakes on devolution are over.

But party insiders have also stressed how the recommendations of the Strathclyde Commission - set up by the Scottish Tory leader to investigate extending devolution - will not jar with Scottish Labour's proposals, as Tory high command recognises Labour is the party in Scotland that will consolidate devolution.

Last month, The Herald revealed how the Scottish Conservatives' "radical" proposals would "chime" with those of Labour and the Liberal Democrats and would be "in the same ballpark" as their plans for more tax powers.

Over the weekend, it was suggested the Tories would propose Holyrood be given power over all income tax, making it responsible for raising 40% of Scottish revenue.

This would empower MSPs to set higher or lower rates than the rest of the UK and would be offset by a cut in the annual block grant Scotland gets from Whitehall.

It is thought there will be calls for more powers for Holyrood on issues such as housing benefit but the Tories will strongly oppose devolving powers such as corporation tax to Edinburgh.

Ms Davidson said: "These new powers - giving MSPs partial control over income tax - will come on stream soon and will be an important stepping stone for us.

"But I think we can develop those powers further: the Prime Minister does too."

She added: "Central to our plans is a commitment to give Holyrood more responsibility. We cannot continue with a pocket-money Parliament which gets its allowance from Westminster and then spends it as it pleases.

"We must move to a new system that brings real accountability to Scotland's politics. In short, the buck must stop at Holyrood."

She added that the current system, where funding is allocated to Holyrood by Westminster "incentivises the manufacturing of grudge and grievance".

A senior Tory with close ­knowledge of the Strathclyde Commission proposals stressed: "This time the Tories will not be putting the brakes on.

"We will not be making the mistakes of the past."

As previously reported, the commission proposals will be launched in Glasgow, where it is believed most of the undecideds in the referendum campaign are.

The Tories' approach is a world away from 1997 when the party staunchly opposed devolution.

It is also a significant departure for Ms Davidson, who campaigned to be the Scottish party leader on a platform of drawing a "line in the sand" on more powers.

During a recent visit to Scotland, David Cameron made it clear that a No vote was not a vote for the status quo but one that would lead to enhanced devolution, echoing Labour and the LibDems.

The Prime Minister stressed how the UK Parliament had passed legislation to hand more powers, including tax powers, to Holyrood from 2016.

But, recognising the support by voters for greater devolution, he made it clear that even more powers would be handed over, though was not specific on which ones.

But the SNP has flatly rejected suggestions from the pro-Union camp that a No vote would lead to more powers for Holyrood.

Alex Salmond, the First Minister, insisted: "Nobody will believe Tory promises of more powers for Scotland." His deputy, Nicola Sturgeon, stressed: "The only way to guarantee more powers for the Scottish Parliament is to vote Yes."