Nicola Sturgeon has suggested struggling accident-and-emergency units in England should look to Scotland - despite coming under attack from the Tories and Labour over the SNP's stewardship of the NHS north of the border.

Both Tory leader Ruth Davidson and Labour's Kezia Dugdale challenged the First Minister over a delay of at least three years in delivering a new network of specialist NHS trauma centres.

The Scottish Government said in 2014 that four major trauma centres in Aberdeen, Dundee, Edinburgh and Glasgow would be operational from 2016.

On Wednesday, however, Ms Sturgeon conceded the ''scale and complexity'' of the changes meant full implementation would ''take at least three years''.

When pressed on the hold-up at First Minister's Questions, she said her programme for government last year had only committed to conclude the preparatory work for the project by the end of 2016.

She added that "many of the improvements" planned would be put in place over the course of 2017.

Ms Davidson told her it was originally planned the trauma centres would receive their first patients in 2016.

The Scottish Conservative leader said: "Communities have been expecting these centres for two years and now have been told at least another three.

"I think they deserve a fuller explanation than the one given."

She demanded Health Secretary Shona Robison come to the chamber to "give a full statement on the delay".

Ms Sturgeon rejected this, saying: "Can I just point out to Ruth Davidson I'm standing in the chamber right now, answering questions right now from her on major trauma centres.

"If she can't get any or all of the information about this that she wants, I would suggest that's about a deficiency in her ability to ask questions, not about any lack of information from the Scottish Government."

She also attacked the Tory leader for raising the issue of the NHS after the Red Cross warned of a ''humanitarian crisis'' in the health service south of the border - a description denied by NHS England.

The SNP leader said: "It's a bit rich for Ruth Davidson to come to this chamber and talk about the health service in the week that the Red Cross has accused her party of presiding over a humanitarian crisis in the health service in England."

Statistics show that while Scotland's accident-and-emergency (A&E) departments are not meeting the target of treating 95% of all patients within four hours, the performance of the NHS north of the border is the best in the UK in this regard.

Ms Sturgeon told MSPs: "We provide appropriate support to health boards so they can continue to improve services and deliver better services to patients.

"Perhaps if the Government in the rest of the UK was doing similarly there would be better A&E performance across hospitals in England.

"As an aside, the latest figures for England on A&E have been published this morning, they show a further decline in performance and they now show a gap in performance between Scotland's A&Es and performance in England's A&Es of 10 percentage points."

She continued: "There is no complacency on the part of the Government, we will continue to see demand for A&E services increase during January and winter as we always do, and that will be reflected in performance.

"But if there is best practice in the NHS in terms of A&E anywhere in the UK to be learned from, it is best practice in the NHS in Scotland."

Figures for A&E departments in Scotland for the week ending January 1 showed that "out of every 100 patients, 92 were seen within the four-hour target", according to the First Minister.

She praised the efforts of NHS staff, saying: "It's worth saying our A&E services face challenges, particularly in the winter months, and these are challenges not just faced in Scotland but across the UK.

"Our staff are doing a sterling job in dealing with those challenges.

"Obviously, my concern, my responsibility, is for Scotland but I think it is important to say due to actions we have taken to support accident-and-emergency departments across Scotland our NHS is coping better than the NHS in other parts of the UK.

"There is no complacency in this Government when it comes to A&E or any other healthcare services, but we will continue to support our health service and our A&E departments to make sure they continue to deliver the services patients deserve."

However, Ms Dugdale claimed the "only consistent thing the SNP delivers is broken promises on the NHS".

The Scottish Labour leader said: "Last year I met with leading consultants and surgeons at the Aberdeen Royal Infirmary.

"They told me that a new trauma centre in Aberdeen could be the difference between life and death for people in the north-east.

"Whether it's someone in a serious car crash or an accident on the rigs, they were clear - having access to world-class trauma care could be a lifesaver.

"The SNP promised the trauma centres would be open in 2016 but yesterday the First Minister announced a three year delay and she looked like she was celebrating that delay.

"Given what the experts tell us, does the First Minister accept that this delay could be a matter of life and death?"

Ms Sturgeon responded: "The Aberdeen and Dundee major trauma centres will actually be fully operational as major trauma centres before the ones in Edinburgh and Glasgow, probably over the next year to 18 months, so Aberdeen is getting the lifesaving major trauma centre that actually some people thought it shouldn't get at all because there should only be two based in Glasgow and Edinburgh."

She emphasised the centres were not brand-new facilities from scratch and that hospitals were already providing "excellent" trauma care which an integrated network would enhance.

Ms Sturgeon added: "Yes, there is much more work to do but we will continue to support our NHS in doing so.

"If Kezia Dugdale was standing in my place right now the health service would have less money than it does. That's why she's got a cheek to come and ask the questions that she's doing."