“I started about two months ago,” David Burns, a 37-year-old teacher living in London, told AFP.
“I used to pick up insulin once a month. Now I’m picking it up about once every two weeks and I am just going to keep doing this until I can be reassured that it is going to be OK.
“But it’s likely we are heading for a no-deal Brexit and our country is in a very precarious position.”
Many of Britain’s 3.7 million diabetics, who include Prime Minister Theresa May, depend almost entirely on insulin imports from continental Europe.
The hormone, which is usually produced by the pancreas, helps diabetics regulate their blood-sugar levels.
A no-deal Brexit would almost certainly mean re-establishing customs and health controls, which could lead to delays at the border.
London and Brussels have both said they want to avoid this scenario but nerves are fraying as the March 29 departure date looms.
“We definitely do hear that people are making sure that their stocks are a bit higher than usual,” Robin Hewings, chief policy officer at Diabetes UK, told AFP.
‘May disrupt medicines supply’
Hewings played down fears of a “national shortage” but warned that there could be localised issues.
Suppliers in Britain have tried to get ahead of the problem, exceeding the government’s recommendation to have enough inventory to last six weeks.
Novo Nordisk, which supplies more than half of the insulin used in Britain, has doubled its reserves.
“We will continue to build stock ahead of March 29 when we expect to have around two and a half times our normal stock levels (roughly 17 weeks) in readiness for a potential no-deal Brexit,” the group said.
French group Sanofi, which produces insulin near Frankfurt, Germany, has also stocked up on drugs in Britain, including enough insulin to last 16 weeks.
US firm Eli Lilly, another insulin producer, said it had “done everything in its power to prepare for Brexit” but warned that “circumstances outside of our responsibility may disrupt medicines supply”.
“A no-deal Brexit would result in the UK’s complete and sudden disassociation from decades of partnership with the EU on medicines regulation and drug safety monitoring,” it added.
‘Not something I want to test’
Diabetes UK and another group, JDRF, have called on the government to provide more details on its preparations in case of a no-deal.
They point out that in addition to insulin, people with diabetes use other drugs and imported products such as needles, insulin pumps, and devices used to measure blood glucose levels.
The health ministry has sought to reassure those affected, and has welcomed the efforts of the pharmaceutical industry.
“We are confident that, if everyone does what they should do, the supply of medicines will be uninterrupted in the event of a no-deal,” a ministry spokesman told AFP.
The ministry’s plans include fast-track emergency medicine deliveries by sea and by air in case of congestion at the border.
But not all patients are comforted by the government’s words.
“If I don’t have insulin then I would go immediately to hospital because, you know, I could be sick in a matter of days and dead in a matter of weeks,” said Burns.
“This is not something I want to test.”