PATIENTS at Scotland's busiest children's hospital have called on people to stop flouting its no smoking rules as the health board unveils a crackdown on people who light up in their grounds.

Children fed up with breathing second-hand smoke on their way to and from treatment at the Royal Hospital for Sick Children at Yorkhill in Glasgow are behind a new no smoking poster campaign, with signs posted around the entrances to the hospital.

Wardens are also patrolling the grounds to ensure the ban is enforced.

One of the poster designs is by Reece Newlands, 13, from Cumbernauld, who has Crohn's disease.

"When you're unwell, the last thing you want is someone inflicting their smoke on you," he said. "We're already sick. That's why we're in or visiting hospital."

Dermot Murphy, paediatric oncologist at the hospital, said: "Smoking outside our hospitals is not just unpleasant but the second-hand smoke moves through windows, air ducts and lift shafts to contaminate wards.

"Patients who are already sick should not have to suffer this and we also know second-hand smoke makes people with breathing problems more unwell."

The move comes as new research found that smokers who cut down on the number of cigarettes they smoke do not go on to live any longer.

Researchers said that people who quit completely went on to have lower mortality rates but there was no difference between those who started smoking fewer cigarettes and those who continued lighting up as regularly.

Professor Linda Bauld from Stirling University, one of the paper's authors, said: "Reducing the number of cigarettes you smoke is not a reliable way of improving your health in the long term.

"However, what we do now know is that it may have a valuable role as a step toward giving up altogether."