"These results strongly support what we suspected - people who eat a lot of red meat, particularly well-done red meat, such as fried or barbecued, seem to have a higher likelihood of bladder cancer. This effect is compounded if they carry high unfavourable genotypes in the HCA-metabolism pathway," he said.

But Dr Alison Ross, Cancer Research UK's senior science information officer, was more cautious about the results.

Dr Ross said: "The link between diet and cancer is complex and difficult to unravel, but we know that eating lots of red and processed meat can increase our risk of some types of cancer.

"More research is needed before we can say for sure whether or not regularly eating red meat affects bladder cancer risk, and if the way it is cooked has an impact. For now, our advice remains to eat a balanced diet that is low in fat, processed and red meat, and rich in vegetables, fruit and fibre."

Dr Ross added: "Smoking is the most important preventable cause of bladder cancer, so giving up is the best way to cut your chances of getting the disease."

Source: Cancer Research UK