DEREK Mackay has admitted signing up to a new Scottish ‘car tax’ without carrying out any economic analysis of how it would work.

The Finance Secretary said the SNP government only agreed to support the Green proposal for a Workplace Parking Levy as a “necessary budget concession” for 2019/20.

Amid a growing public backlash, a rattled Mr Mackay accused other parties and the media of “scaremongering” over the controversial plan as he was grilled about it by MSPs.

However he also suggested the levy could be watered down by creating a host of new exemptions to ensure public sector workers, such as teachers, did not have to pay it.

READ MORE: Plans for a new tax on workplace parking spaces condemned as a 'mess'

Mr Mackay said councils should “look very closely at local circumstances” when considering possible exemptions when imposing a WPL.

“Teachers is a very good example. If it’s local authorities making the decisions, then surely those councils will think about schools.”

He also insisted Transport Secretary Michael Matheson was now in charge of the policy.

Under a last-minute budget deal last week, the Government agreed to back a Green amendment to the Transport Bill currently going through Holyrood to create a WPL.

At the government's request, the Bill is now being delayed to allow for a belated public consultation on the scheme.

The plan will empower Scotland’s 32 councils to charge employers for each workplace parking space in order to cut congestion, with an automatic exemption for NHS workers.

In Nottingham, where the council charges £415 a year for each space, employers often pas on the cost to staff, including the council itself clawing back costs from teachers.

The idea was one of several demands the Greens secured in return for back the minority SNP government's budget.

Giving evidence on the 2019/20 budget at the finance committee, Mr Mackay was asked by Labour’s Neil Bibby if there had been any economic modelling or impact analysis of the plan.

Mr Mackay replied: “No, I haven’t undertaken any individual economic analysis.

“This is not a Scottish Government scheme, this is about the empowerment of local government. It was a necessary budget concession, because if there was no budget the consequences were that a £42.5bn budget for Scotland would have gone down.

“But ultimately this is about empowering local authorities.”

READ MORE: Teachers 'should be exempt from paying new workplace parking tax'

Urging Mr Mackay to carry out an economic analysis, Mr Bibby suggested all Scotland’s councils would need to impose a levy because their budgets were being squeezed, and asked how much it would raise if it followed the Nottingham model.

Mr Mackay accused him of having “no evidence” that the scheme would be used by all 32 Scottish councils or follow the Nottingham model.

He said: “I agree with the need to consult, to engage. That’s something that I would certainly encourage the parliament and local authorities to do before deploying any power.”

Mr Bibby asked whether other, non-NHS workers should be also exempt from the levy, such as teachers, police officers, firefighters, apprentices and people on low incomes.

He said: “What about workplaces with poor [public] transport for example?

“Workers in your constituency at the leatherworks in Bridge of Weir have to start their shift at 6 o’clock, long before the first bus arrives.

“Do you not think there’s a case for looking at these issues before pressing ahead?”

Mr Mackay replied: “Yes, I do happen to think there's a case for further exemptions, and I do happen to think local authorities should look very closely at local circumstances when taking this forward. That will be a matter for local authorities.

“I think there are further cases for local authorities to look at exemptions and local circumstances, and of course all that should be taken into account.

“Teachers is a very good example. If it’s local authorities making the decisions, then surely those councils will think about schools. There’s an important issue to address here - the charge isn’t for individuals, the charge would be ultimately to the employer.

“There is a question about which employers pass that on, but we mustn’t immediately conclude that it is the individual staff member that pays the charge, when the scheme should be about the employer, the property owner.”

READ MORE: Workplace parking tax 'falling apart' amid unanswered questions, Tories claim

Earlier, Tory Alexander Burnett asked Mr Mackay who would maintain a register of all workplace parking spaces, and how it would affect business rates.

Mr Mackay said: “I don’t propose to offer up any more detail because it’s at an early stage.

“We’ve agreed in principle to accept an amendment that introduces a power for local authorities to take this forward.

“There will be consultation by that committee [Rural Connectivity] and the detail will be forthcoming. But this is at an early stage

“The Scottish Government did have one proviso on this - that the NHS and hospitals would be exempt from this. If there are other exemptions or matters for local authorities to consider, that will be considered in due course.

"But I think maybe members shouldn’t scaremonger on this, should work with parliament in a constructive and collaborative fashion to ensure we get a scheme that’s right for the country, right for local authorities and right for local people.”

Mr Burnett suggested the scheme was “unworkable” and created “just to buy off the Greens”.

He also claimed most SNP MSPs didn’t support it.

Mr Mackay said there was an “absence of facts” around the issue.

He said: “The budget deal that I have taken forward has the full support of the Scottish Government and members of my own party.”

He said businesses were far more concerned about the impact of Brexit.

He said: “It’s true to say that whatever people think about the workplace levy, it is s nothing compared to the financial catastrophe that’s coming our way as a consequence of Brexit.

“That is what businesses are talking about and want clarity on right now.”

Green MSP Patrick Harvie suggested blue badge holders and employers who subsidized public transport could also be exempted from the WPL.

He said: “It’s not whether one single model should be imposed across all of Scotland - because absolutely nobody has suggested that - the question for parliament is whether local councils should be, as they are now, effectively forbidden from even considering whether they can design a scheme that suits their own local circumstances."

Mr Mackay said that was a “fair analysis” of the dichotomy politicians faced between parliamentary control versus local discretion.

READ MORE: Glasgow business group criticises plan to subject firms to workplace parking tax

Separately, at the Rural Economy committee, which is handling the Transport Bill, Tory convener Edward Mountain said the Government has asked for the legislation to be delayed.

The second of the Bill's three stages was originally pencilled in for late March or April.

Mr Mountain said: “At this stage we do not know what that delay is going to be.

“This delay was partly on resource capacity in the Scottish Government, and partly on the announcement that very afternoon that the Scottish Government will bring forward an amendment to the Bill at stage 2 to introduce workplace parking levy.”

Scottish Green MSP John Finnie said he would bring forward the amendment, and suggested the delay would allow the committee the opportunity to take evidence on it.

He added: “Certainly I would be very keen to make available the wording of the amendment to facilitate that.”

Scottish Conservative finance spokesman Murdo Fraser said: "This is a tax imposed by Derek Mackay, yet he couldn’t answer any of the key questions surrounding it.

"He failed miserably to give workers and businesses the detail they are asking for, and even admitted he’d barely given the matter any thought before including it in his budget.

"This tax is already falling apart, which is no surprise from an idea concocted by the Greens and the SNP."