Banning smoking in public places could save more lives more quickly than developing a single new anti-cancer drug, a leading charity has said.
Cancer Research UK says a public smoking ban would save lives
Cancer Research UK says preventing smoking in pubs, cafes and other work places could save 5,000 lives a year.
It is to encourage politicians to back a ban to protect hospitality staff and encourage social smokers to give up.
Health chiefs in Glasgow are also urging the Scottish Executive to ban smoking in public places nationwide.
Cancer Research UK makes its call for legislation in a manifesto to be presented to the three main political parties at their party conferences.
The charity sets out its top 10 priorities for the next government to tackle the disease in Cancer Challenge: Agenda for Change.
Among them are demands for responsible marketing of food, especially junk food, and a call for greater investment in medical research and specialist cancer staff.
Scientists estimate that non-smokers who are exposed to smoke at work increase their risk of developing lung cancer by nearly 20%.
CANCER RESEARCH UK'S PRIORITY LIST
Implement ban on smoking in work places and enclosed spaces without further delay
Promote responsible food marketing and limit junk food adverts
Spend 1.5% of the total NHS budget on medical research
Recruit and train sufficient skilled staff for cancer treatment
Protect the right of patients to take genetic tests without fear of discrimination
Safeguard the future of research by investing in universities
Cancer Research UK's chief executive, Professor Alex Markham, said the charity was committed to finding the best ways to treat cancer through drugs and other treatment.
But he said the risk to health posed by second-hand smoke remained a real concern.
He said: "I believe a single piece of legislation would be the most effective thing we could do to save lives when you compare it with the time and money it takes to develop a first-class drug.
"In a recent poll of more than 4,000 people, four out of five said they would support a law to ensure enclosed workplaces are smoke-free."
Prof Markham said health professionals across the UK believed people had the right to breathe clean air.
Scotland's First Minister Jack McConnell has said he is actively considering a ban in Scotland.
Cancer experts in Glasgow estimate more than 100 people lose their lives each year because of passive smoking, with a further 2,500 dying from smoking-related illnesses.
A ban on smoking in public places introduced in Ireland is widely considered to have been a success.
In July, Chief Medical Officer for England Professor Sir Liam Donaldson said a ban in public places could save up to £2.7bn.