Nicola Sturgeon has accused Ruth Davidson of “playing” to Ukip after the Scottish Conservative leader defended Theresa May’s plans to cut immigration to the tens of thousands.

The SNP leader also sought to brand the Scottish Tories as a branch office of Mrs May’s party, suggesting they would do anything the Prime Minister asked.

Polls suggest that the Scottish Tories could pick up as many as 11 seats at the General Election, mainly from the SNP.

Amid clashes during BBC Scotland's leaders'' debate, Ms Davidson claimed next month's election was a "massive opportunity" which gave Scotland "the chance to move on from the divisions of the past".

But she came under concerted attack from all parties for her support for the Tory manifesto target to cut net immigration to less than 100,000.

Ms Sturgeon said that she was “astounded” to hear the Scottish Tory leader support a policy which would “be devastating for the Scottish economy”.

The SNP leader added: “We’ve got a need in this country to grow our population. If EU migration was to be ended over the next 25 years, even constrained, we would see our working age population fall while our pensioner age population is due to go up by 50 per cent.

“That would be an economic catastrophe.

“I think it is disgraceful that we have a Tory Party that plays to Ukip, and in doing so puts the needs of our country on the line.”

Scottish Liberal Democrat leader Willie Rennie said that Ms Davidson had called Foreign Secretary Boris Johnson “a liar” over his claims on immigration during a televised debate before the Brexit referendum, and questioned whether the Scottish Tory leader was lying now.

Ms Davidson accused him of “scaremongering” over the immigration issue.

Asked if she agreed with the pledge to cut immigration below 100,000, she said: “Net immigration? Yes.

“I think you have to have an immigration system that is trusted, and I think that when you lose the trust of people that is when you get social unrest.”

Earlier she told the SNP: "Fix our schools, don't split up our country. Champion our businesses, don't put a border at Berwick."

Kezia Dugdale, the Scottish Labour leader, said that despite Scots voting against both independence and Brexit in 2014 and 2016 respectively "what we've got is hard Brexit and the SNP hellbent on a second independence referendum".

Ms Davidson was later booed as she told Ms Sturgeon "you only want one thing (independence)... the country said no and you won’t listen to them."

But Ms Sturgeon also came under fire over the Scottish Government’s record on health and education.

One member of the studio audience Claire Austin, who works as a nurse with NHS Lothian, told the First Minister that she was forced to rely on foodbanks because of her NHS salary.

A female maths teacher told Ms Sturgeon that the record Higher and Advanced Higher passes the First Minister boasted about were the result of lowering the standard of exams.

“If you’re going to lower the standard of exams then you would see passes rising,” she said.

Another audience member, a male teacher with 40 years’ experience, attacked successive government for embracing fads in education.

He said: “What we’re talking about is a fifth of our primary schools leave primary without basic literacy and numeracy skills, which isn’t good.”

He also said he had heard of schools receiving money from the SNP’s flagship £120m attainment who could not hire permanent staff, and so bought furniture instead.

There was also a heated exchange between Ms Sturgeon and Ms Dugdale who accused the SNP leader of telling a “porky” after Ms Sturgeon said the attainment gap between the richest and poorest students was narrowing.