A senior clinician at the country’s maiden Nightingale hospital has called for military expertise to help protect the mental health of staff and volunteers at the “exhausting” facility.

Professor James Calder, who had a 14-year military career, said it was crucial to call on veterans who have worked in challenging situations around the globe as the UK rapidly expands its hospital care capacity to deal with the unprecedented challenges of the Covid-19 outbreak.

Prof Calder, one of the clinical leads at NHS Nightingale in east London, said he was sceptical about the new facility when he was brought on board but had been overwhelmed by its early success.

He told the PA news agency: “When I looked at it a few weeks ago I thought: ‘That’s nigh-on impossible.’

“I was very suspicious about how on Earth we’re going to deliver this. But it’s gradually evolved and you realise: ‘This can work now.’

“When we turned up here for the first time we said: ‘Wow – this is a big empty space, it’s got water, it’s got electricity, it’s got a roof, and nobody’s shooting at you.’

“So actually this is achievable – that’s not necessarily the case in other theatres we’ve been working in.”

Prof Calder, 52, from Winchester, added: “Being a clinician it’s been incredibly impressive looking at how a very effective, high quality intensive care unit has been set up in – effectively – a warehouse.

“Somebody said you’re on the train and laying the tracks ahead of you as you are going along – and that’s absolutely right, you just have to make sure the train doesn’t go too quickly and run away with you.”

He said part of the success has been through dedication to staff welfare, many of whom are working “pretty exhausting” 12-hour shifts.

But he said Nightingale workers have borrowed a technique deployed on military operations where staff are paired with a buddy upon arrival for their shift, encouraging them to look out for one another throughout.

He said: “If you have eyes with each other when you first go on a shift, you introduce yourselves, and speak to each other after the shift. If they get upset, have a difficult time with a patient or a death, they sit down and have a cup of tea. It worked very well in the past in the military and it’s working very well here.

“We are using their knowledge over many years working with the military to produce a package that is safe for our staff.”

Captain Carol Betteridge, who ran the field hospital in Helmand Province during British presence in Afghanistan and now works for military charity Help for Heroes, said: “There are some really good NHS guidelines (on looking after staff) but we found in the military that not one thing works for everybody.

“We looked at our experiences with the veterans through traumatic experiences and developed an online field guide to self care.

“Because the veterans have co-produced that, we know that these are things that have worked for them and we hope for NHS staff.”