In a statement released on social media around 1:30pm local time, NHS Digital stated that it was aware users were experiencing “issues with accessing the Covid Pass” and said its technicians were working to resolve the problems. At close to 5pm, it updated its Twitter account to confirm the pass was now “operational” again.

During the outage, social media users complained about their inability to show they had been double-jabbed – a requirement to travel abroad to many countries – sparking concern and fears of missed flights.

Under current rules, Britons travelling abroad or entering certain events or venues can be asked to show either proof of vaccination or that they have recently tested negative for the virus.

The inability to access the app came hours after the NHS posted on social media about how more than 10 million people have registered to use the service, giving them easy access to their Covid pass and medical information.

Fortunately for residents in England, the rules are slightly more relaxed than in neighbouring Wales and Scotland, where those patronising nightclubs or large events must present a Covid pass before entry under strict measures to reduce the risk of spreading the virus. England had considered taking a similar step, but the government said last month that it would seek to avoid enforcing Covid vaccine passports “if we possibly can.”