Nicola Sturgeon has accused Scottish Conservative leader Ruth Davidson of having "lost the plot" after the Tory claimed Scotland's "crippling" teacher shortage was being worsened by government bureaucracy.

Ms Davidson said there were more than 550 teachers who had qualified outside of Scotland and who had been told they could not take up a post north of the border.

She raised the example of a couple who moved to Scotland five years, saying the man had been told to "go back to school" and retrain before taking a teaching post, despite having worked in England as a maths teacher for 15 years.

The Conservative leader challenged the First Minister on the issue after it emerged that a shortage of maths teachers has forced the head at Trinity Academy in Edinburgh to appeal to suitably qualified parents to help out - similar to a situation which arose earlier this year in a school in Education Secretary John Swinney's Perthshire constituency.

The SNP leader however insisted her Government had fixed the problem saying teachers who had gained their qualification next year could now take up a teaching post on a conditional basis, while they worked towards becoming registered in Scotland.

Ms Davidson had pressed her at First Minister's Questions at Holyrood, saying the Tories wanted those who had trained as teachers elsewhere to be "fast-tracked" into Scotland's classrooms.

She said: "Yesterday we received an email from a couple who moved to Scotland five years ago, the husband did his teacher training in maths and he worked down south for 15 years as a maths teacher.

"When he moved here he was told he couldn't teach maths anymore without a full years retraining as a student.

"That is a qualified maths teacher not allowed to teach maths in Scotland. And he is not alone.

"We have a crippling shortage of teachers but according to evidence presented to this Parliament this year we have more than 550 qualified teachers from outside Scotland applying to teach here but who have been told by this government to go back to school themselves."

Ms Sturgeon hit back, saying: "I received that email as well yesterday, so I have been able to look into it.

"My answer is going to include something I thought Ms Davidson would have known, but since she clearly doesn't I'm going to tell her about it.

"The circumstances narrated in that email relate back to 2012, since then - and this is the bit I would have thought Ruth Davidson, if she was going to raise this today, might have actually have been aware of - because since then the General Teaching Council for Scotland has introduced provisional conditional registration, which allows teachers qualified outside Scotland to become registered and to take up a teaching post in Scotland while they work towards meeting the minimum requirement."

The First Minister added: "Ruth Davidson asks me why haven't we fixed that. Well I'm afraid Ms Davidson the answer is we have, you just didn't bother to do the research to find out.

"That individual, while he would not have been able to teach in 2012 may now be in a position to do so, which is why we will now be contacting that individual to see if he wants to take up a teaching post.

"That is a change in circumstances that frankly I'm quite gobsmacked Ruth Davidson didn't bother to find out before she came here today."

Scottish Labour's interim leader has called on the First Minister to guarantee there will be no further fire service job losses amid "growing concerns" about staff levels.

Alex Rowley said more than 700 frontline fire fighter staff have left the Scottish Fire and Rescue Service (SFRS) and highlighted cuts to the number of fire safety inspection officers.

The Fire Brigades Union (FBU) told a Holyrood committee on Wednesday reductions to fire safety inspection officers should be addressed as a matter of urgency, with the number down by almost a quarter (24%) since 2013/14.

Speaking at First Minister's Questions, Mr Rowley said: "It is of course the responsibility of government to make sure the fire and rescue service have the resources that they need.

"I have talked with many firefighters and have met with the Fire Brigades Union and I have to say there are some serious concerns being raised. Despite assurances from the Ministers to protect the frontline, the FBU say that over 700 frontline firefighter jobs have gone.

"There are growing concerns about adequate staffing levels and the future of fire stations. Will the First Minister give an assurance to parliament that there will be no further job cuts in our fire service and no programme of fire service closures introduced across Scotland?"

Nicola Sturgeon said: "I give an absolute assurance that we will continue to work with the fire service and work in dialogue with the FBU to make sure we are protecting those who keep us safe from fire.

"We have sought to do that and we will continue to work to do that both in terms of the number fire officers and others who work in the fire and rescue service and in terms of the configuration of fire stations across our country."

She said the government had increased the fire service's operational budget by £21.7 million this year and added: "It is a responsibility of the fire and rescue service to make sure they have the right staff doing the right jobs in the right place."

The First Minister added that there were 68 uniformed fire safety enforcement officers across Scotland as well as 13 non-uniform auditing officers and a team senior fire officers competent in fire safety enforcement, giving round the clock cover.