All watches should be banned from exam halls as more devices become connected to the internet, an inquiry into cheating has found.

The Independent Commission on Examination Malpractice, set up by exam boards to investigate the prevalence of cheating in public exams, warned that invigilators increasingly could not tell the difference between smartwatches and traditional watches.

Though the body said cheating was rare, it said the increasing “sophistication of internet-enabled devices” meant a blanket ban on watches was appropriate. Smartwatches, mobile phones and other internet-enabled devices are already banned in exam halls.

Sir John Dunford, the commission’s chairman, said: “It can look as if it’s a time-telling watch and actually, you press a button and it becomes an email-type watch. If you don’t ban them all I think you’re giving a very difficult job to invigilators who are looking round an exam room. So I think the obvious thing to do here is to ban watches.”

The Joint Council for Qualifications (JCQ), which commissioned the review, said it would consider whether to ban watches for next summer’s exams, as well as the report’s other recommendations.

The report also recommended that exam boards monitor the dark web for the illegal sale of exam papers and said toilet sweeps, to check for hidden notes and phones, should be carried out during exam periods.

It called for more awareness of increasingly sophisticated technologies used to cheat, such as miniature cameras in the bridge of glasses and microphones hidden under a false nail.

The commission also said exam boards should carry out more research into why there had been sharp rise in schools requesting extra time for pupils taking exams. There has been a 13% rise in the number of approvals for special arrangements during an exam for candidates with special educational needs, disabilities or temporary injuries, and a 27% rise in applications for special considerations to be made following an exam.

The latest figures for England show that 2,735 pupils were penalised for cheating last year, marginally fewer than the year before. “In all walks of life, there is a small proportion of dishonest people and the education system is no exception,” said Dunford. “There is a lot more that can be done to prevent malpractice by both staff and candidates.”

Mark Bedlow, the chair of JCQ, which represents exam boards, said: “The commission’s findings show that the system is robust and that very little malpractice occurs due to the diligence and professionalism of those involved. However, the commission has noted a number of areas for improvement of our systems to further minimise incidents of malpractice.”