Adverts for a smartphone GP service that promised NHS doctor appointments "in minutes" have been ruled misleading by the Advertising Standards Authority.

The service offers a symptom-checker and free GP consultations via videolink on smartphones.

The ASA received complaints that the ads did not say users would first have to leave their GP, and registration could take up to three weeks.

GP at Hand said it thought the process was "self-evident".

Another criticism upheld was that the ads did not state that potential users must live within 40 minutes of one of five surgery catchment areas in London in order to see a GP in person.

The ads were displayed on the London Underground transport network as well as online between November 2017 and February 2018.

Babylon Healthcare Services, which runs GP at Hand with a group of London GPs, said the sign-up process and eligibility criteria were clearly displayed on both the GP at Hand app and website.

"We think the process of 'registering' is self-evident and clearly understood by the public," said a spokesman.

The ads have now been tweaked to make that process more visible, he added.

However, the ASA ruled that people would have to make a "transactional decision" to seek out the website or app - and only then would they find out out whether they were eligible.

The free service was launched in 2017 and claims to have 32,000 users.

It has the backing of Health Secretary Matt Hancock, who has said he uses the service.

The ASA said it had received complaints from eight people about the adverts, one of whom was a GP.