Humza Yousaf has been accused of “channelling his inner Liz Truss” with his surprise plan to freeze council tax.

The Liberal Democrats said the First Minister trashed his recent deal with local authorities and “abandoned” cabinet government when he made the announcement at SNP conference.

It followed deputy FM and finance secretary Shona Robison being unable to tell MSPs how much the freeze would cost and where the money would come from.

She said it would be a matter of “negotiations” with the council umbrella body Cosla and part of the Scottish Government’s budget process for 2024/25.

TheTories called the plan an “utter shambles” and “desperate, back-of-a-fag packet stuff.”

In an apparent attempt to wow voters before the general election, Mr Yousaf announced the tax would be frozen next April to help with the cost-of-living crisis.

The freeze involved U-turning on the Scottish Government’s own recent proposal to raise bills for Band E to Band H homes by between 7.5% and 22.5% to raise an extra £175m.

Local authorities will also have to be compensated for not raising the tax as part of their annual budget setting, which will cost at least £100m to offset a 3% rise, but potentially far more, as most councils raised the charge by more than 5% last year, one by 10%.

Cosla has complained vociferously about the way the announcement came out of the blue, despite Mr Yousaf signing the “landmark” Verity House Agreement in June. 

This promised councils “no surprises” on budget issues. 

Cosla expressed its “extreme disappointment that the First Minister chose to undermine the spirit and the letter of the Verity House Agreement, so soon after it being signed”.

In urgent questions at Holyrood, LibDem MSP Liam McArthur likened Mr Yousaf’s announcement to the chaos seen in the brief premiership of Ms Truss last year.

He asked Ms Robison: “With the First Minister’s unilateral decision to freeze council tax, the Verity House Agreement has gone the way of the Historic Concordat [agreed by ALex Salmond with councils], Fergus Ewing has had his wishes granted with the shredding of the Bute House Agreement [to govern with the Greens], civil servants have been circumvented, cabinet government been abandoned. Does the Cabinet Secretary believe that the First Minister was right to channel his inner Liz Truss over council tax?”

She replied: “This is a decision that will help 2.5million households, including those in the member's constituency. I would have thought in the midst of a cost-of-living crisis that that would have been something he would have supported. 

“What we've heard here is the sound and fury of the opposition about process. What we've not heard from any one of them is whether or not they will support the council tax freeze as part of their budget for 2024/25. 

“I think that's what the public wants to hear the opposition telling us.”

Earlier, Tory MSP Liz Smith asked Ms Robison how much the freeze would cost and where the money would come from to pay for it. 

Ms Robison replied: “When I met with the Cosla presidential team, we agreed and I offered for that process to be a negotiation with Cosla, and that negotiation will take place to ensure that the council tax freeze is fully funded. 

“Of course, that figure will be part of the budget process for 2024/25. 

“It's important that it is a negotiation. That is something that we believe is important. 

“What I would want to hear from the opposition, though, is perhaps less about process and more about the principle of whether they support the council tax freeze or not. 

“We'll see during the budget process whether they do or not.”

Ms Smith replied: “What an extraordinary answer.”

She then reminded Ms Robison that she told the Holyrood finance committee two weeks before Mr Yousaf’s conference announcement that the Verity House Agreement involved giving councils “more flexibility” around their money to help with local decision-making. 

Ms Smith said freezing council tax removed that flexibility and asked Ms Robison if she had known when she said it that Mr Yousaf was going to announce the freeze a fortnight later.

Ms Robison failed to give a direct answer, saying: “We have given local authorities more flexibility. The second homes and empty homes [council tax] premiums that will be able to be applied are also part of giving local authorities more flexibility and we are keen to discuss with local authorities what more flexibility can be given.

“In terms of the process, which Liz Smith clearly wants to remain talking about, we requested and received advice from officials on the concept of the council tax fees and gave that advice full consideration. 

“On balance. We made the decision to freeze the council tax taking into account the impact of sustained inflation caused by, of course, the Tory government economic policy on households in Scotland. 

“I acknowledge the concerns expressed by local government about the manner of that announcement [and] substance, but we believe it is the right thing to do to help over 2.5 million households at these difficult times.” 

Ms Smith said later: “The SNP’s screeching council tax U-turn has been an utter shambles. “The Cabinet Secretary told the finance committee that the Verity House Agreement would give councils ‘more flexibility’ – but Humza Yousaf’s volte-face does exactly the opposite.

“Councils are in an impossible position because of the SNP’s refusal to provide them with a fair funding deal – and vital services are endangered as a result.

“Shona Robison not only couldn’t say how much this new policy will cost, or where the money is coming from, but she even admitted that the basis for funding is still up for negotiation. This is desperate, back-of-a-fag packet stuff.”