One of Nicola Sturgeon’s key Covid advisers has said people should permanently avoid cruise ships because of the potential for various infections to spread on board.

Devi Sridhar told the Edinburgh International Book Festival today: “I would say, as a public health person, don’t go on a cruise ship ever.” 

Ms Sridhar, the Professor of Global Public Health at Edinburgh University, had been discussing the inadequacy of UK Government advice in the early days of the pandemic.

Despite China instituting lockdowns, “the only advice was, like, don’t go on cruise ships if you’re over 70, and I’m not joking,” she said.

Prof Sridhar, who in February 2020 described cruise ships as “floating germ factories”, went on: “I would say, as a public health person, don’t go on a cruise ship ever.

“I know, that’s going to get me in trouble. I have had a cruise. 

“Is there a legal on this event? I have had a cruise.

“The cruise industry lobbyists wrote [to] me very upset about my comments about cruise ships.

"But I just think cruise ships and infectious diseases are… they’re not meant to go together.” 

At the start of the pandemic, some of the highest profile outbreaks outside China were on cruise ships.

The British-registered Diamond Princess was quarantined for weeks in a Japanese port after several passengers tested positive. 

The virus went on to infect 712 of the 3,711 passengers and crew and 14 died.

When it returned to the UK, passengers then fell ill and spread the infection on land as well.

Before the pandemic, Scottish ports served 27 cruise lines operating 67 different vessels.

In 2019, there were almost 900 calls and over 800,000 cruise passengers visiting Scotland.

A recent Scottish Government commissioned report estimated the Scottish cruise industry supported more than 800 workers and generated £23m for the economy.

It was seen as particularly important for extending the tourist season in Orkney and Shetland.

Prof Sridhar later stuck by her previous view an independent Scotland could have coped better with Covid, as it would have far greater powers over borders and finance

She said Scotland came tantalisingly close to eliminating Covid last summer, but then new variants came in from overseas, as it could not control the flow of people.

Prof Sridhar also discussed the constant attacks she received on social media, including being accused of “witchcraft” and being responsible for the pandemic.

She said her university bosses had also been anxious over some of her own posts including one about a Nigella Lawson chocolate cake.

She said: “One Sunday I made a chocolate cake for breakfast in the middle of January and I ate it. It was Nigella's cake and it was yummy.

“I just tweeted it, saying I had a cake for breakfast and I got complaints to the University of how I was promoting unhealthy dietary habits, and how could I be a professor of Public Health, and be having obesity and like telling this, which made me realise I should stay away from cake.

“I remember my line manager coming to me with a smile, you know, and talking to him and him being like, Did you have to tweet your cake?

“I didn't think of that. I was really proud of myself baking something, and I wanted to share it.

“It's a millennial thing. We just like sharing and of course people think it's reckless.”