NICOLA Sturgeon has stood by Scotland's under-fire chief medical officer after it emerged she flouted her own coronavirus guidelines by visiting her seaside holiday home twice. 

Dr Catherine Calderwood, who has been given a warning from Police Scotland over her conduct, apologised unreservedly for breaking her own rules.

She insisted: "This was a mistake, human error, and there's no excuses."

Dr Calderwood has come under intense pressure to resign, with opposition parties insisting her position is now "untenable". 

Critics also raised concerns over a "cover up" amid shifting messages over Dr Calderwood's rule-breaking.

The expert has appeared in official information adverts urging the public to stay at home to save lives and protect the NHS.

The First Minister said Dr Calderwood was wrong to visit her second home in Earlsferry, Fife, but insisted she needed the chief medical officer to focus on her job. 

She dodged questions about whether Dr Calderwood had offered to resign.

Ms Sturgeon said: "The chief medical officer made a mistake in travelling away from her home. Whatever her reasons for doing so, she was wrong and she knows that.

"It was not in line with the advise we are asking everyone to follow. She has apologised unreservedly to me and to the public, and she's right to have done so."

She added: "All of us, including me, will make mistakes in these unprecedented times we're living in. When we do, we must be candid about it and learn from it. 

"That is what I know the chief medical officer is doing. In making abundantly clear that she was wrong, we will underline the reasons why we are asking everyone to comply with this advice.

"But what I also know is that over these past few weeks as we have been dealing with this crisis, her advice and expertise has been invaluable to me and continues to be so. 

"If I'm to do what I need to do to steer the country through this crisis to the very best of my ability, I need her to be able to focus on the job that she is doing. 

"A job that, notwithstanding her mistake on this, she is doing extremely well. 

"So I'm not expecting you not to be angry about this mistake, nor is she. 

"But I am asking you to consider the wider importance to the government and by extension teh country of being able to count on the continued expertise of the chief medical officer at this critical time as we fight this virus."

Ms Sturgeon made the comments during a press conference in Edinburgh, during which she was repeatedly quizzed over Dr Calderwood's position. 

The First Minister said she did not know the chief medical officer had spent two weekends at her coastal retreat until being approached by the Scottish Sun on Sunday. 

Dr Calderwood earlier issued a full apology.

She said: "I have already issued a statement this morning apologising unreservedly for travelling away from my home while restrictions are in place.

"As well as this weekend, it's important to be clear that I also was there last weekend with my husband. 

"I did not follow the advice I'm giving to others. I'm truly sorry for that.

"I've seen a lot of the comments from members of the public on Twitter today – people calling me a hypocrite, people telling me about the hardships they have endured while following my guidance. 

"My office has also received emails from members of the public making clear to me their disappointment and unhappiness at what I've done.

"People have told me that I'm irresponsible, that I have behaved as if my advice does not apply to me. 

"I want people to know that I have seen all of that, and that I've heard the comments. 

"What I did was wrong. I'm very sorry. It will not happen again. 

"I know how important the advice is that I have issues. I do not want my mistake to distract from that. 

"I don't want to make the jobs of the police or my NHS colleagues any harder, and I apologise to them as well. 

"I have a job to do as chief medical officer to provide advice to ministers on the path of this virus and to support the medical profession as they work night and day to save lives. 

"This was a mistake, human error, and there's no excuses.

"I should not have done what I did. I'm very sorry about that.

"I've spoken to the police this morning about this and I'm sorry for taking up their time on this when it could have been avoided. 

"Having spoken with the First Minister this morning, my intention is to continue to focus on my job."

Police Scotland Chief Constable Iain Livingstone said officers had visited Dr Calderwood and issued a warning about her conduct.

Calum Steele, general secretary of the Scottish Police Federation, suggested the extent of Dr Calderwood's rule-breaking may have been covered up. 

His comments came after she admitted to visiting her holiday home twice.

This appeared to clash with a Scottish Government statement issued to the Scottish Sun on Sunday on Saturday night. 

It made no mention of an earlier visit, and said Dr Calderwood "took the opportunity this weekend to check on a family home in Fife as she knows she will not be back again until the crisis is over".

It added: “She stayed overnight before returning to Edinburgh. In line with guidance she stayed within her own household group and observed social distancing with anyone she was in passing in the village."

Mr Steele tweeted: "Two consecutive weekends makes this not just an issue of judgement but one of integrity. You can always survive a c*ck up. You can’t a cover up."

He previously said policing the pandemic had been made more difficult and stressed checking on a second home is not one of the "reasonable excuses" providing an exception to emergency coronavirus legislation.

Photos of Dr Calderwood and her family near a coastal retreat in Earlsferry were published in The Scottish Sun late on Saturday.

Just days earlier, the 51-year-old tweeted a photo of her family at their main residence in Edinburgh as they clapped for the frontline NHS staff working to stop the spread of Covid-19.

Earlsferry is a drive of more than an hour from Edinburgh.

Last month, the Scottish Government issued a travel warning criticising the "irresponsible behaviour" of people with second homes and campervans travelling to the Highlands in a bid to isolate.

In a joint statement, Scottish Liberal Democrat leader Willie Rennie and Wendy Chamberlain, the MSP and MP respectively for the area where Dr Calderwood has her second home, said: "It is difficult to see how the chief medical officer will be able to carry the important messages about the virus and the lockdown if she has not even followed it herself."

They added: "If we are going to get through this pandemic we need medical leaders who everyone can follow. It is with great regret that we say that the chief medical officer will need to go."

Scottish Labour's health spokeswoman Monica Lennon also called for Dr Calderwood to stand down, Scottish Conservative leader Jackson Carlaw said her position is "untenable", and the Scottish Greens said she can "no longer credibly front" the public health campaign.