English people who have had one of their two coronavirus vaccinations in Scotland, Wales or Northern Ireland are not eligible for a Covid passport on the NHS app, it has emerged.
Separate data collection in each nation of the UK means that different areas have their own systems for proving vaccination status.
The NHS app’s Covid-19 certificate feature, which works only in England, will show Britons who have had one vaccine in England and another elsewhere as having received just one dose.
“At the moment, vaccines administered overseas or in Scotland, Wales or Northern Ireland cannot be recorded within the NHS England vaccinations database so no vaccine certificate is currently available from the NHS,” an NHS customer service representative told one patient.
The NHS is looking into the issue in the hope that it can be resolved by Monday, when nightclubs and large event spaces have been urged to use the app to verify that customers have had either two vaccinations or a negative test.
The app is also used by people in England who wish to prove they have been jabbed to go on holiday.
The pace of the UK's vaccination roll-out is slowing
People seeking a vaccine certificate in Scotland have been asked to request a paper passport by calling a centralised hotline, while in Wales, passes are distributed digitally.
In Northern Ireland, users can request a paper copy or digital version of the certificate, which has a QR code.
It is unknown how many English people could be denied a Covid pass by the database quirk.
From Monday, when coronavirus restrictions ease in England, a Covid certificate will become required to visit some hospitality venues.
The certificates are not legally required, but the Government has asked nightclubs and large events to make them a condition of entry.
A poll by the Night Time Industries Association, a trade body, found that just 17 per cent of venues planned to make them mandatory for customers.
Ministers also sparked a backlash from the hospitality industry and Conservative MPs when new guidance was released this week asking pubs and restaurants to consider using the passes.
Venues can scan the passes with the NHS Covid Pass Verifier app, which was released on Friday on the Apple app store and Google Play store for Android devices.