Deaths from lung cancer in Britain might fall by half by 2020 because of the success of anti-smoking campaigns, the Cancer Research Campaign forecast last night.

The disease now claims 35,000 Britons each year, making it the biggest killer among cancers, but it is likely to be overtaken by cancers of the prostate, breast and bowel, according to projections.

Prostate cancer, which kills 10,000 men annually in the UK, is likely to become more widespread as the population ages, although earlier detection and new drugs might help prevent deaths from this and other cancers.

However, breast cancer claims more women than lung cancer at present, said the CRC, which will outline predictions about cancer trends at the Global Conference for Cancer Organisations in Brighton today.

And there would be a huge increase in deaths from smoking-related cancers in developing countries because of the way tobacco companies are targeting them, cancer specialists said.

The CRC warned of more cancers of the bowel and oesophagus in all countries because of heavy drinking, bad diet and lack of exercise.