RUTH Davidson has been dragged into the ugly civil war engulfing the Tories, putting the Scottish party's hopes of coming second at the Holyrood election in jeopardy.

The Scottish Tory leader tried to distanced herself from the row over plans to slash £1.3bn a year from disability benefits yesterday but dodged commenting on the Government’s specific welfare proposals.

SNP, Labour and Liberal Democrat politicians united in calling for her to break her silence and reveal whether she backs taking cash off some of the most vulnerable people in society.

The Tory party is split over Government proposals to change elements of the daily living component of the Personal Independence Payment (PIP) scheme.

PIPs provide financial support for people with disabilities and long-term health problems, but the plan is believed to affect 640,000 claimants and will reduce the bill by £4.4bn over several years.

Iain Duncan Smith, the long-standing Cabinet Minister for Work and Pensions, resigned in protest on Friday over a move that raids disability payments at the same time as cutting tax for higher earners. The shock move threw the party into chaos.

He described the proposals as “not defensible” and was replaced yesterday by former Secretary of State for Wales Stephen Crabb. The Prime Minister has backed a rethink, but has not promised to scrap the cuts package.

The plan has been likened to Osborne’s budget announcement last year on cutting tax credits for the lowest paid, a policy he abandoned after an outcry.

However, the spotlight is now on Davidson, who is days away from leading her party into a historic Holyrood election campaign. Opinions polls suggest the Scottish Tories may pip Labour for second place in May, but the disability cuts are a looming threat to Davidson's hopes.

She backed the budget proposals for tax relief for higher earners, but has not rushed to express a view on the benefit cuts.

In a statement released yesterday on Crabb’s appointment, she declined to offer a direct opinion on the PIP cuts and restricted herself to general comments on welfare reform, saying: "Unlike Labour and the SNP, the Conservatives have sought to tackle the many failings of our welfare state, getting thousands of long-term unemployed people back into work. We must ensure the route back into a job is always worth the effort. And we need to reassure people who can't work that they will be given the support and dignity they deserve.

"I hope Stephen's appointment marks the start of a fresh focus – right across government – on building a better welfare state. We must not let the huge long-term benefits of welfare reform be sullied by short-term cuts.”

However, a senior party source said Davidson would be “frustrated” by such a controversial change being announced at this sensitive time.

Davidson has a positive working relationship with the Prime Minister, but it is understood she and the Chancellor are not close. She was against his tax credit plan and it is believed she is not enthusiastic about him succeeding Cameron as PM.

Davidson once said she would like the next UK Tory leader to display “warmth as well as intelligence”, a comment that could be seen as a dig at the Chancellor.

Scottish Liberal Democrat leader Willie Rennie demanded that Davidson explain her position: “We need to hear from her how she justifies the cruel cuts to PIP. Ruth Davidson has been silent on this important matter whilst others have felt they had no choice but to leave the cabinet. Her silence over these cuts is deafening. She needs to explain herself. Does she stand by George Osborne and his cuts or back Iain Duncan Smith?"

Labour MSP Iain Gray said: “When the man who introduced the bedroom tax quits over cuts then you know it's time to break from Tory austerity, but Ruth Davidson won't even break her silence. Now that her close ally in Westminster is in charge of wielding the axe, Ruth Davidson has to break her silence, or else it will show once and for all that she is just another Tory like George Osborne and David Cameron.”

SNP MSP John Mason said: “I would expect the Scottish Tory leader to have an opinion on this issue. We are just moving further and further away from the sort of welfare state most of us signed up to.”

Meanwhile, Tory divisions deepened yesterday. Ben Harris Quinney, chairman of the Conservative think tank the Bow Group, said Tory Ministers and backbenchers are unhappy.

“I think there's a recognition within the Conservative Party that this is hugely unpopular with the country ... and George Osborne's authority has effectively been challenged by Iain Duncan Smith by saying that, you know, 'the Conservative Party isn't really with you on this George'."

Tory MP Bernard Jenkin, an ally of Duncan Smith, said: "A lot of colleagues will be extremely annoyed at this explosion but they will not be surprised.

"I think the high-handed and short-termist political approach that the chancellor has tended to take to the management of other departmental budgets has tested the patience of more than one minister."

However, Stephen McPartland, the Tory MP for Stevenage, criticised Duncan Smith’s record on welfare reform:

“I am sorry, but I will not be shedding any tears for the evangelical, aggressive and routinely failing welfare reforms that were the personal fiefdom of the secretary of state for DWP."

Trade union leaders also criticised Duncan Smith’s record. Tim Roache, GMB general secretary, said it was a "shame that it's taken Iain Duncan Smith six years to get his head round the fact that the government is benefiting the richest, rather than working people, let alone the disabled".

Mark Serwotka, leader of the Public and Commercial Services union, said the former Cabinet Minister had "presided over years of suffering and surely ranks as the most hated Work and Pensions Secretary in living memory".