British travellers were left struggling to board flights after the NHS Covid Pass system went down for several hours on Thursday night.

Users trying to access proof of their vaccination status via the NHS app and website found that the service was unavailable, with the app telling users: “We are sorry the NHS Covid Pass is currently unavailable.

“At this time there is no alternative route for accessing this information via the NHS app or online. If you have already downloaded the information then your access should not be affected.”

At around 10pm, NHS Digital tweeted: “The Covid-19 pass is now working as normal and we will continue to monitor overnight. Thank you for your patience and apologies for any inconvenience caused.”

Holidaymakers on social media said they had been unable to check in at airports because they could not prove their vaccination status.

One user wrote on Twitter: “It is unacceptable to leave people without a workaround – we are flying out to Spain in the early hours for our first family holiday for five years and have no proof of vaccination!!

“Please provide an urgent update for those travelling now, this has to be bare minimum.”

Another user tweeted: “Rather than echo what everyone else is saying. Instead of fixing the app, which is taking hours … Can Covid pass proof be sent by email to everyone with an NHS login? Or any other temporary fix so that people aren’t missing travel and holidays?”

Another user wrote: “Please hurry – we are trying to check in but need the Covid pass to complete this.”

The requirement for people to show the NHS Covid pass to visit indoor and outdoor events and venues, such as cinemas and nightclubs, was scrapped by the government in February.

However, it is still used as a way for people to show their vaccination status when travelling abroad to certain countries.