Lung cancer symptoms: What are the warning signs?

It's one of the deadliest forms of cancer, killing tens of thousands in Britain and the US every year.

And there are usually no noticeable symptoms of lung cancer until it is advanced.

Warning signs develop as the cancer progresses, spreading through the lungs and reaching other parts of the body.

Dame Esther Rantzen, 82, yesterday revealed she has been diagnosed with the cruel disease but confessed that she is 'remaining optimistic'.

The legendary broadcaster and activist also said the cancer has spread and that she is undergoing tests to assess the best treatment.

Dame Esther, who founded charities Childline and The Silver Line, said she wanted to go public with her diagnosis as she is struggling to 'skulk around various hospitals wearing an unconvincing disguise'.

'In the last few weeks I have discovered that I am suffering from lung cancer which has now spread,' she said.

'At the moment I am undergoing various tests, to assess the best treatment.

'I have decided not to keep this secret any more because I find it difficult to skulk around various hospitals wearing an unconvincing disguise, and because I would rather you heard the facts from me.'