Doctors and Nurses will face the sack for smoking cigarettes, even if they are not on hospital premises at the time, under draconian new rules.
Staff at Guy's and St Thomas' hospitals in London are among the first in the country to be told they must "cover up" their uniforms while smoking off-site or risk losing their jobs.
Those seen smoking while displaying a hospital ID badge will face disciplinary procedures up to and including dismissal.
“[Smoking off-site] is difficult to enforce, but if they are seen with their uniform on and their badges on it will be tackled in the same way as if they were smoking on-site," the trust's director of workforce Ann Macintyre told the Evening Standard.
"When you put these things in you get a bit of kick-back initially, but people do adapt. We recognise that people may still want to smoke, but they’ll also have to go off-site and cover up."
The rule change follows guidance from the National Institute for Health and Care Excellence last year, recommending that all NHS hospitals and clinics become smoke-free.
Smoking groups described the new rules as "bullying" and "inhumane".
Most hospital trusts already operate smoking bans for staff on site, but Guy's are one of the first to enforce a ban off-site.
The guidance has also hit staff who live in hospital accommodation.
Staff at Addenbrooke Hospital in Cambridge say they have now been banned from smoking in their own homes.
One cleaner at the hospital claims the ban has already put his colleague's safety at risk.
Richard Heath told the Cambridge News that a woman living in hospital accommodation had been threatened on a dark footpath after leaving the hospita in order to smoke.