Many patients are smoking in "secret"
Attempts to ban smoking on psychiatric wards are simply driving the habit underground, a survey suggests.
The Mental Health Foundation found only a minority of wards in England have implemented the ban successfully.
Respondents cited problems such as safety concerns, the rise of "secret smoking" and staff dissatisfaction with a policing role.
But the government's mental health tsar said he had visited many trusts where a ban had been smoothly implemented.
Some 85% of 109 respondents to the survey said the ban, which came into effect in July 2008, had not been implemented effectively.
Many said patients had taken to smoking in secret, with staff feeling the need to turn a blind eye, particularly when patients were very unwell.
Another problem highlighted by respondents was that many units did not have safe outdoor space where patients could smoke.
Drain on resources
Even where such a space existed, respondents reported that the need to escort patients outside to smoke was a considerable drain on staff time and resources.
Many respondents also said they were uncomfortable with their enforcement role - especially where patients had no opportunity to smoke outside.
Some staff reported feeling more like police than nurses, and others said that patients had reacted aggressively when asked to stop smoking.
Many staff also raised concerns about the possible fire risks presented by covert smoking and the disposal of cigarette butts.
Report author Simon Lawton-Smith said the ban was justified on health grounds, but enforcement was beset by widespread practical difficulties.
He said: "Where access to an outside space is limited or unavailable, staff seem to be in the difficult position of either risking breaking the law by turning a blind eye, or denying a patient the right to smoke completely."
The report found that widespread staff and patient consultation had been key to success in those units who had implemented a ban effectively.
Offering smoking cessation support such as nicotine replacement therapy was also important.
The report calls on the Department of Health to carry out a formal view of the impact of the smoking ban.
Vicki Nash, of the mental health charity Mind, said: "Forcing people to stop smoking abruptly on admission to hospital when they are already likely to be distressed is inappropriate and could heighten anxiety.
"People with mental health problems are twice as likely to smoke than the general public so it's vital that trusts are equipped to deal with this and can either support patients to quit or resource the option to smoke outside."
Louis Appleby, the National Director for Mental Health, said other research had shown that although implementing the smoking ban had posed challenges, most trusts believed it had been done successfully.
Professor Appleby said: "I have visited many trusts who have implemented the ban with little or no difficulty.
"Mental health wards are being transformed for the better and going smoke-free is part of this.
"We believe that mental health staff and patients deserve the same healthier, smoke free environment as the rest of the NHS and there are no plans to change the policy."