Dame Sally Davies said the government could not guarantee there would be no deaths if the UK crashes out of the EU without an agreement and insisted that patients’ lives were at risk.
The stark warning came ahead of last-ditch talks between Boris Johnson and taoiseach Leo Varadkar on Thursday, in which they agreed they could ”see a pathway to a possible deal” despite a war of words between London and Brussels.
After the meeting, Mr Varadkar told reporters the talks were at a “very sensitive stage”.
Health unions have sounded the alarm over the disruption to supplies of life-saving medicines in a no-deal scenario, as many cannot be safely stockpiled.
Dame Sally told the Today programme: “The health service and everyone has worked very hard to prepare.
“But I say what I’ve said before, we cannot guarantee that there will not be shortages – not only of medicines but technology and gadgets and things.
“And there may be deaths, we can’t guarantee there won’t.”
Asked if patients’ lives are at risk, Dame Sally replied: “They are at risk.”
Government no-deal papers published this week said plans were in place for a chaotic departure, including a dedicated support unit for suppliers of medical goods in the health sector, with the aim of helping to ensure that companies have the necessary customs paperwork in place for border arrangements ahead of a no-deal scenario.
A Department of Health spokesperson said: “We fully understand the concerns some people have about the availability of medicines. We are doing everything we can to help ensure they can access the treatments they need after Brexit.
“The government, industry and NHS have put in place robust preparations for Brexit, which consists of stockpiling, securing transport and warehouse capacity and working closely with businesses on their readiness for day one.”
Business minister Kwasi Kwarteng insisted there was still a “good chance” of securing a Brexit deal, despite an escalation of rhetoric from both sides in recent days.
“The main point is a deal – which was written off as something impossible - is actually something that is possible and we are working very hard,” he said.
However, the EU’s chief Brexit negotiator Michel Barnier said there was still no basis for a fresh agreement as the bloc had yet to see any “operational, legally binding solution” to replace the Irish backstop ahead of next week’s European Council meeting.
Mr Johnson’s “two borders” proposals, he said, were based on a system “that hasn’t been properly developed, that hasn’t been tested”.
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