Patients in Essex have been told that due to a delay in production of the flu vaccine the first vaccination appointments of the year will be available from November 2 – two days after the UK potentially exits the EU with a deal.

NHS England said earlier in the year that flu vaccines generally start to be distributed from September each year.

However, vaccine manufacture involves complex biological processes and there is always the possibility that initial batches of vaccine may be subject to delay, or that fewer doses than planned may be available initially.

Patients in Dunmow were told the news in a letter sent out by the town’s John Tasker House surgery, which comes after warnings from doctors that a no-deal Brexit would make it “likely” there will be a delay in flu vaccine supply this year.

Delays in deciding what strains of flu to use in the vaccine mean many doses will have to be imported after October 31.

“What we can see is we’re likely to not have enough flu vaccine, we are likely not to have the flu vaccine coverage that we’ve had in previous years, and that is likely to have an impact on the NHS,” Prof Andrew Goddard, president of the Royal College of Physicians, told Newsnight last month.

However a spokesman for West Essex CCG, which covers Dunmow, said that the NHS national team as recently as Monday was advising there should be no major problems expected in the flu vaccine supply this year.