Jackson Carlaw launches bid to 'take down' Nicola Sturgeon and the SNP

He said: “I have spent the last 18 months taking on Nicola Sturgeon. I am asking you now to let me spend the next 18 months taking her down."

The First Minister immediately hit back on social media.

Ms Sturgeon wrote: "Tough man talk - but didn’t he just ‘take me on’ in the general election and lose half his seats?

"On the strength of that performance, he’s certainly my favoured candidate for Tory leader!"

Mr Carlaw, who was Ms Davidson's deputy, said he would initiate an urgent review of Scottish Tory policies, including potentially changing its stance on tuition fees and welfare reform.

The MSP made the comments as he launched his party leadership bid at the Dynamic Earth visitor attraction in Edinburgh.

He is running against Michelle Ballantyne, the Scottish Tories' social security spokeswoman, to lead the party into the next Holyrood election in 2021.

He said the Scottish Tories wanted to “redress the balance” for middle earners in Scotland, such as teachers, police officers and nurses.

Those earning more than £27,000 currently pay more tax in Scotland than they would in England.

Mr Carlaw said cutting taxes for top earners is not an immediate priority, and that the party would instead focus on middle Scotland.

He said: “Making Scotland the highest taxed part of the UK is a dead end if we want to encourage a new generation of Scots to come and work here, and we have to do so much more for that next generation.

“So yes, we have to start redressing it, but it’s that group of people, between £26,000 and maybe £45,000 – they’re the people we really need to do a heck of a lot to improve the lot of.

“They shouldn’t be paying more for doing the job they’re doing to advance their lives, their families, to the benefit of Scotland.

“We need them, and we need to reward them for their effort and success.”

Mr Carlaw also outlined his opposition to plans for a workplace parking tax, insisting it is “regressive, unjust and plain wrong”.

He said the Scottish Tories would restore the more than 2,000 teachers lost under the SNP.

Meanwhile, the party’s childcare policy would “offer fully flexible provision when parents want it and not just when some official says they can have it”.

Elsewhere, Mr Carlaw insisted the 2014 independence referendum was a “once in a generation” event, citing comments made by SNP leaders at the time.

Asked to define a ‘generation’, he said it meant “different things to different people”, adding: "There were two referendums between our votes on Europe.

"And that seemed to me like a pretty good interval of time to take place."

He added: “The key thing is, I know what a generation is not.

“And a generation is not any time soon, in the next five years, or even the next ten.

“A generation, at the very least, is a period of time that all of us understand it to be – and it ain’t what Nicola Sturgeon is suggesting, which is no generation at all."

Mr Carlaw has the backing of the vast majority of Tory MSPs.

Ms Ballantyne, meanwhile, has yet to secure the public support of any MSP or MP.

She is expected to formally launch her campaign to be Scottish Tory leader next week.

Writing in The Herald at the weekend, she said “serious lessons” need to be learned after the party lost half its seats at the general election.

She insisted it would be wrong to “pat ourselves on the back for a result that saw our vote share fall since 2017 and saw us lose half of our seats”.

Ms Ballantyne said the Tories had failed to pitch a “truly aspirational blue-collar policy offering” in Scotland, unlike in areas where the party took seats from Labour down south.

She said: “There is no room for continuity or complacency. Change is needed.”

Ms Davidson stepped down as Scottish Tory leader in August last year, citing both her “conflict” over Brexit and the birth of her son Finn.