NICOLA Sturgeon has hit out at opposition leaders who criticised the SNP's Budget deal with the Greens, defending what she said were her government's "fair and progressive" tax policies.

Ruth Davidson said the new tax rates were too high for wealthy people. Richard Leonard said the new tax rates were too low for wealthy people.

But it was the hapless Leonard in particular who was the main focus of the First Minister’s scorn, and much laughter from the government benches as he attempted to push his “alternative budget”.

Sturgeon, much to the amusement of her own MSPs, poked holes in the Labour leader’s proposals, and told Leonard to “go back to the classroom and do his homework on tax before he comes and questions me again on it in this chamber”.

During a feisty FMQs at Holyrood, Sturgeon had been asked by Leonard why she was “refusing to ask the richest people in Scotland to pay their fair share”.

She replied that that was exactly what her government was doing. She said that, while the Tories seemed to only want a tax cut for the richest, all that Scottish Labour had provided was “an incompetent tax policy”.

Labour’s policy, she said, would not only require legislative powers that the parliament didn’t have, but they would also go against Audit Scotland recommendations. Therefore the only relevant part was the income tax portion of Labour’s proposals - and they did not take into account any behavioural analysis, she pointed out.

The Scottish Fiscal Commission (SFC) is responsible for estimating what money tax policies would raise, and it would take behavioural changes into account in its analysis. The Scottish Government can only spend what the SFC estimates will be raised.

Sturgeon pressed Leonard on this point on which he seemed to be unaware, before attacking his claim that a Labour budget would raise a billion pounds. She stated that it would be closer to £300 million, and that would be “generous”.

She said Labour's "completely incredible and incompetent" tax proposals did not take into account the impact that increasing the top rate to 50p could have on people's behaviour.

“Labour sums simply do not add up,” she said.

Leonard responded to say that research had suggested raising taxes would not lead to higher tax avoidance, before asking why Nicola Sturgeon was not using her powers to raise the top rate of tax. Sturgeon pointed out that, actually, she was. Under the Scottish Government's planned income tax changes, the two highest rates of the levy will be increased by 1p.

Sturgeon then said, again, that regardless of what other research may exist the SFC’s opinion legally must be observed when budgeting as they determine how much money the government can spend.

"It's like Richard Leonard is suggesting we fund our NHS through Monopoly money or something,” she said.

“If Richard Leonard wants to be taken seriously, he's really going to have to go back to the classroom and do his homework on tax before he comes and questions me again on it in this chamber."

Patrick Harvie, co-convenor of the Scottish Greens, also defended the budget, saying it had prevented cuts to local authority funding.

He also challenged Sturgeon to address how councils fund services in the future, saying: "It's perfectly true that (council umbrella group) Cosla have welcomed the change to the budget and that will protect services across Scotland, but they also say ... that there are long-term financial challenges ahead and those can only be expected to grow in the future.