Just 1.8oz (50g) of processed meat daily increases the chances of getting bowel cancer by around 20%.

The charity World Cancer Research Fund (WCRF) said more needed to be done to get across the message that people who eat processed meat regularly are putting their health at risk.

Professor Martin Wiseman, medical and scientific adviser for the WCRF, said there was convincing evidence of a link between processed meats and cancer.

Processed meat is defined as that which is preserved by smoking, curing, salting or the addition of preservatives. Examples include ham, bacon, pastrami, salami, hot dogs and processed sausages. Hamburgers and minced meat counts if it has been preserved with salt or chemical additives.

Prof Wiseman said research has shown that only 30% of Britons were aware that eating processed meat increases cancer risk.

He added: "We are more sure now than ever before that eating processed meat increases your risk of bowel cancer and this is why WCRF recommends that people avoid eating it.

"The evidence is that whether you are talking about bacon, ham or pastrami - the safest amount to eat is none at all. When you consider that eating 50g of processed meat a day can increase your risk of bowel cancer by about a fifth, it is clear that you can make a positive difference by cutting out as much as possible.

"We do recommend that people avoid it completely, but it is not a case of all or nothing. Cutting down the amount of processed meat you eat can also reduce your risk of developing bowel cancer.

"But we need to do more to get this message across because if two thirds of people don't know about the link between processed meat and bowel cancer, then they are not in a position to be able to make informed decisions about whether to eat it or not."