Experts have voiced growing frustration over the UK government’s claim that it is “following the science”, saying the refrain is being used to abdicate responsibility for political decisions.

They also raised concerns that the views of public health experts were being overlooked, with disproportionate weight given to the views of modellers.

“As a scientist, I hope I never again hear the phrase ‘based on the best science and evidence’ spoken by a politician,” Prof Devi Sridhar, chair of global public health at the University of Edinburgh, told the Guardian. “This phrase has become basically meaningless and used to explain anything and everything.”

The government has repeatedly said it is being “led by the science” on decisions ranging from banning mass gatherings to closing schools, the use of face masks and, most recently, the prospects of lifting the lockdown.

However, Sridhar and others argued that scientific views on these topics could be wide-ranging and dependent on a scientist’s field of expertise.

The diversity of scientific views was apparent in March when case numbers were rising rapidly but the government chose not to ban mass gatherings or introduce wide-reaching physical distancing.

“World Health Organization advice, and what we’ve learned from lots of previous outbreaks in low- and middle-income countries, is that the faster you move at the start, the better, because it’s exponential growth,” Sridhar said. “In public health, a test, trace and isolate campaign would’ve been where your mind first went.”

Instead, she said, the government appeared to be basing policy on the presumption of a binary choice between two scenarios, played out in computer models, of either eradicating the virus or it becoming endemic.

Play Video 3:27 What the UK's coronavirus death toll is not telling us – video explainer

Prof Mark Woolhouse, an infectious diseases epidemiologist at the University of Edinburgh, said modelling had had a disproportionate influence. “I do think scientific advice is driven far too much by epidemiology – and I’m an epidemiologist.

“What we’re not talking about in the same formal, quantitative way are the economic costs, the social costs, the psychological costs of being under lockdown,” he said. “I understand that the government is being advised by economists, psychiatrists and others, but we’re not seeing what that science is telling them. I find that very puzzling.”

Woolhouse said that while it was understandable that saving lives was the top priority, the idea of doing this at any cost was naive.

“With any disease there is a trade-off. Public health is largely about that trade-off. What’s happening here is that both sides of the equation are so enormous and so damaging that the routine public health challenge of balancing costs and benefits is thrown into incredibly stark relief. Yet that balance has to be found.”

Others expressed concern about the lack of transparency around the evidence affecting decision-making. “We don’t know who sits on Sage [the government’s scientific advisory group for emergencies], we see very little of the papers that go to Sage,” said Prof Sheila Bird, the former programme leader of the Medical Research Council’s biostatistics unit at the University of Cambridge. “That scientific underpinning is not evident.”

Sridhar said the failure to fully consider the perspectives of experts beyond epidemiology may have contributed to misguided decisions. Models appear not to have factored in the role of hospital staff shortages, which may have diverted attention from the urgent need for adequate personal protective equipment, she said.

The concept of shielding the most vulnerable “looks beautiful” in models, she said, but in reality care homes are facing major outbreaks and multigenerational households are struggling to isolate the vulnerable. “You can’t take these people out of the system and isolate them as if they were a data point on a graph,” she said.

“There’s a real problem if you have a collection of people from the same background, the same field, the same institutions; that can lead to blindspots and groupthink,” Sridhar added. “Diversity is clearly important for better decision-making.”

Some fear the prominence given to science in supporting political decisions risks burdening scientists with unrealistic expectations and could ultimately erode trust in their expertise.

“The government isn’t using expertise simply to validate claims, it also appears to be using it as an insurance policy,” Prof Christina Boswell, a political scientist at the University of Edinburgh, wrote this week. “If things go wrong – and the curve gets too steep – it will be the scientific advice that is to blame.”

Who’s who: the experts

Prof Chris Whitty: the truthteller

Chief medical officers have a tradition of speaking their mind, often to the chagrin of governments. Whitty, however, has appeared to be in perfect harmony with the UK government at the Downing Street briefings on Covid-19. The reality is probably that ministers are in step with him – or even a step behind. On Wednesday, Whitty, a practising NHS consultant physician, told a starker truth than politicians have dared: that physial distancing needs to be in place until at least the end of the year.

Sir Patrick Vallance: the political naif

Vallance has had a career in medicine at University College London and St George’s, University of London, researching vascular biology and endothelial cell physiology, and also in the pharmaceutical industry. From 2012 to 2018, he was president of research and development at GlaxoSmithKline, where, unusually for the industry, he advocated greater openness about innovation and partnerships with other companies.

He left to become the government’s chief scientific adviser, but is not an instinctive politician. He was partly blamed for the government’s flirtation with the notion of herd immunity, saying in March that the strategy was to reduce the peak, not suppress it completely. “Also, because the vast majority of people get a mild illness, to build up some kind of herd immunity so more people are immune to this disease.” Afterwards it was denied he meant herd immunity should be the goal; it was simply an outcome.

Neil Ferguson: the workaholic

Ferguson leads the modelling behind the UK response through the MRC Centre for Global Infectious Disease Analysis, which he founded with colleagues at Imperial College. He has a long history in modelling epidemics, originally with Roy Anderson’s unit at Oxford University, where they worked on BSE, vCJD, foot and mouth, Sars and swine flu – sometimes attracting controversy.

Ferguson is a mathematician, an epidemiologist and a workaholic who, before the lockdown, moved seamlessly between Downing Street, university and press briefings. Even while recovering from Covid-19 himself, he gave evidence to MPs and did interviews. His team’s work is at the heart of the lockdown strategy, predicting the numbers of deaths it will save.

Dr Jenny Harries: the ‘national treasure’

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The deputy chief medical officer has been called a “national treasure” by Vogue, which may reflect the fact she is a rarity – a woman on the Downing Street briefings podium. With degrees in pharmacology and medicine, she joined Public Health England in 2013. Like her boss, Whitty, she is independent-minded, and she warned at the end of March that the lockdown could last for six months or longer. She also suggested couples living separately could “test the strength of their relationship” during the lockdown by moving in together.

Prof Jonathan Van-Tam: the flu expert

Jonathan Stafford Nguyen Van-Tam is a widely published expert on influenza and the vaccines and antiviral drugs used to treat it. Now one of the government’s two deputy chief medical officers, he is regularly deferred to by Hancock. He spent four years in the pharmaceutical industry before returning to the public sector to head the pandemic influenza office of the Health Protection Agency, which is now part of Public Health England, and was a member of Sage during the 2009-10 swine flu pandemic. His grandfather Nguyễn văn Tâm was the prime minister of Vietnam in 1952.

Prof Stephen Powis: the NHS’s defender

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A kidney specialist, Powis is a professor of renal medicine at UCL and was the medical director of the Royal Free hospital until 2018. Now the medical director of NHS England, his job is to defend it against the threat of Covid-19. As such, his comments at Downing Street briefings have not always stuck to the medical need. With Michael Gove on 4 April, he criticised people sabotaging 5G phone masts under the illusion they were implicated in the spread of the virus. “I’m absolutely outraged, absolutely disgusted, that people would be taking action against the very infrastructure that we need to respond to this health emergency,” he said.