THERESA May is among millions of Britons who face the prospect of drastic drug shortages in the wake of a no-deal Brexit, the head of the UK's medicines regulator has warned.

Sir Michael Rawlins highlighted the case of insulin, which diabetics like the Prime Minister use every day, and which, he pointed out: “We import every drop of it.”

There are some 3.5 million people in the UK with diabetes, including nearly 230,000 in Scotland, many of whom rely on insulin.

Speaking in a personal capacity, the head of Medicines and Healthcare products Regulatory Agency[MHRA] said: “There are problems and the Department for Exiting the EU and the Department of Health and Social Care need to work out how it’s going to work.

“Here’s just one example why: we make no insulin in the UK. We import every drop of it. You can’t transport insulin around ordinarily because it must be temperature-controlled. And there are 3.5m people[with diabetes, some of whom] rely on insulin; not least the Prime Minister,” Sir Michael told The Pharmaceutical Journal.

He added: “Disruption to the supply chain is one of the ways that patients could be seriously disadvantaged. It could be a reality, if we don’t get our act together. We can’t suddenly start manufacturing insulin; it’s got to be sorted, no question.”

His comments came before Matt Hancock, the UK Health Secretary, earlier this week made clear that the Government was looking to stockpile various medicines, including insulin.

He told MPs: "We are working right across government to ensure the health sector and the industry are prepared and people's health will be safeguarded in the event of a no-deal Brexit.

"This includes the chain of medical supplies, vaccines, medical devices, clinical consumables, blood products. And I have asked the Department to work up options for stockpiling by industry,” explained Mr Hancock.

In a statement released on Friday, Sir Michael noted the Secretary of State’s remarks on stockpiling medicines and added: “A responsible Government prepares for a range of outcomes and the Department of Health and Social Care is working to make sure the health sector and industry are prepared and that people's health will be safeguarded."

Nonetheless, his warning caused alarm.

Labour’s Chris Leslie MP, a leading supporter of the People’s Vote campaign, said: “This critical warning from the chair of the MHRA shows just how serious the prospect of a ‘no-deal’ would be for this country.

“Millions of patients rely on insulin every day and the Commons voted in July to instruct the Prime Minister to stay in the EEA medicines regulatory network but the Government seems intent on ignoring this. It is time she accepted there is no majority for ‘no deal’ on this,” declared the Nottingham MP.

Dr Paul Williams, on behalf of the pro-EU Best for Britain campaign, said: "Most of the medical profession are worried about how supplies of medicines, including insulin, will be affected in the event of a no-deal Brexit.

“Professor Rawlins is saying what we all fear: patients will suffer if the Government get this wrong. No deal on insulin would be a very big deal."

In other developments:

*Sebastian Kurz, the Austrian Chancellor, has told Mrs May on her visit to Salzburg: “The Brexit decision is a decision we see very negatively. But, of course, it has been taken by the British people so now we have to find a way to deal with it and, from our point of view, it is important to avoid a hard Brexit."

*following rejection of the PM’s customs plan by Michel Barnier, the EU’s chief negotiator, Czech minister Ales Chmelar also suggested it was unworkable, saying there was a “clear problem” for the EU to delegate control of its borders to a third country;

*Liam Fox, the Trade Secretary, hit back, warning the EU27 it was putting "political ideology" ahead of its citizens' economic wellbeing;

*his fellow Brexiteer, the former minister Steve Baker, claimed Brussels was pushing Britain towards a choice between a no-deal or "capitulation";

*a poll placed the Tories and Labour neck and neck on 38 points with the Liberal Democrats up to double figures on 10 and Ukip on six;

*another snapshot showed only quarter of people believed Mrs May would secure a good Brexit deal with 72 per cent saying they lacked confidence in her ability to reach a good deal with Brussels; her worst rating to date and

*Dominic Cummings, a key figure in the Brexit campaign who refused to give evidence to an inquiry by the Commons Digital Committee into fake news, posted its report into the issue two days ahead of the publication date, tweeting: “F*** the charlatans embargo.”