Boris Johnson's chief aide Dominic Cummings has attended meetings with senior scientists who advise the government over coronavirus, Downing Street has admitted - raising concerns over the impartiality of the group.
A spokesman denied newspaper reports that Mr Cummings is a member of the Scientific Advisory Group for Emergencies, rather, he's just attended "some meetings".
It had been claimed in the Guardian Mr Cummings and Ben Warner, a data scientist who worked with him on the Vote Leave campaign for Brexit, had been among 23 attendees at a key Sage meeting on March 23 – the day Mr Johnson ordered the lockdown.
But Downing Street issued a firm rebuttal, saying "it is not true that Mr Cummings or Dr Warner are “on” or members of SAGE".
The spokesman added: "Others also listen to meetings without being 'on' or 'a member of' SAGE."
Despite the clarification, Mr Cummings' attendance has been criticised, with many suggesting it could have politicised decision making.
Sir David King, a former chief scientific adviser to the government, said he was “shocked” to learn political figures had been allowed into Sage meetings.
“If you are giving science advice, your advice should be free of any political bias,” he said. “That is just so critically important.”
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Sir David told the Guardian there were no political advisers on the Sage equivalent he sat on.
After being told of Mr Cummings' attendance, Sir David said: "Oh my goodness. Isn’t this maybe why they don’t want us to know who was there?"
The report comes amid pressure urging the government to release details of the group's membership - currently details are kept secret, though individual members are able to disclose their participation.
On Twitter, Labour's shadow health secretary asked: "Why are politically appointed special advisors taking part in what should be independent SAGE deliberations?"
He demanded answers and "total transparency" after saying "ministers have repeatedly claimed timing of lockdown was based on science".
Liberal Democrats acting leader Ed Davey said "science should be left to the scientists", adding how "political appointees shouldn’t be at these vital meetings".
He also asked for "transparency" and demanded the government publish the committee’s minutes.
Downing Street says Mr Cummings and Dr Warner have attended some meetings "in order to understand better the scientific debates concerning this emergency".
They also attend "to understand better the limits of how science and data can help government decisions", a spokesman said.
"Occasionally they ask questions or offer help when scientists mention problems in Whitehall."
The spokesman said political advisers "have no role" in the independent scientific advice provided to the government.
He added: "The Prime Minister wants his advisers to understand the scientific debates around Covid as well as they can for obvious reasons.
"From the start the government has tried hard to integrate scientific advice into its decision making in a sensible way. It will continue to do so."
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