Electronic cigarettes are being banned in hospitals because they look too much like the real thing.

Brighton and Sussex University Hospitals NHS Trust is updating its policy to include e-cigarettes in a blanket ban on smoking in its buildings and grounds.

E-cigarettes produce puffs of vapour and deliver a nicotine hit without tar and toxins.

They have been billed as a safe alternative to tobacco and an aid to quitting smoking.

But managers at the trust, which runs the Royal Sussex County Hospital in Brighton and Princess Royal Hospital in Haywards Heath among others, believe the e-cigarettes could cause confusion.

A spokesman said: “The trust’s smoke free working group took the view that some makes of e-cigarette look remarkably similar to ordinary cigarettes, particularly when seen from a distance or at a glance

“Allowing people to use e-cigarettes on site could therefore give the impression that the trust condones smoking on site, or does not actively enforce its no smoking policy.

“During the consultation process, the trust council, the health and safety committee and the hospital management board were all asked to consider this point and the rationale for banning e-cigarettes.”

There has been a rising concern nationally that there has been little research on the effects of using e-cigarettes.

This has led to a growing number of public bodies treating them the same as real cigarettes.

The trust policy also calls for all staff to politely and professionally challenge anyone smoking on trust premises.

However they are asked to apply a combination of professional and common sense judgements, and may use their discretion, exceptionally, in relation to some patients.

These include terminally ill patients or agitated patients in the accident and emergency department who may find that a quick cigarette outside could help to stop them becoming aggressive or violent.

E-cigarettes are already banned at Western Sussex Hospitals NHS Trust and East Sussex Healthcare NHS Trust.

Brighton and Sussex University Hospitals NHS Trust also includes the Royal Alexandra Children’s Hospital and Sussex Eye Hospital in Brighton and the Hurstwood Park Neurosciences Centre in Haywards Heath.