Alcohol is chiefly to blame for an "alarming" rise in the rate of oral cancers among men and women in their forties, it was claimed today.
Experts said the number of 40-somethings developing cancers of the mouth, tongue, lip and throat had increased by a quarter in the past decade.
Smoking and alcohol consumption are the two main risk factors for oral cancers.
But since cancers caused by smoking often take up to 30 years to develop, tobacco is not thought to be the main culprit.
Instead, the finger of suspicion is pointing at alcohol consumption, which has doubled in the UK since the 1950s.
Other risk factors that may be involved include a diet low in fruit and vegetables, and the sexually transmitted human papillomavirus (HPV), which also causes cervical cancer.
Figures produced today by Cancer Research UK show that since the mid-1990s, rates of oral cancers have gone up by 28 per cent for men in their forties and 24 per cent for women.
The charity's health information manager Hazel Nunn said:
"These latest figures are really alarming. Around three quarters of oral cancers are thought to be caused by smoking and drinking alcohol. Tobacco is, by far, the main risk factor for oral cancer, so it's important that we keep encouraging people to give up and think about new ways to stop people taking it up in the first place.
"But for people in their 40s, it seems that other factors are also contributing to this jump in oral cancer rates.
"Alcohol consumption has doubled since the 1950s and the trend we are now seeing is likely to be linked to Britain's continually rising drinking levels.
"It's possible that HPV and diet are also playing a role, and the evidence - particularly for the role of HPV - is growing."
Each year around 5,000 new oral cancers are diagnosed in the UK and 1,800 people die from the disease.
Oral cancers include those of the lip, tongue, mouth, throat and a region called the piriform sinus.
About a third of oral cancers affect the mouth and a slightly lower proportion the tongue.
The most common signs of the disease are ulcers, sores, or red or white patches in the mouth that last longer than three weeks, together with unexplained pain in the mouth or ear.
"The good news is that oral cancer can be treated successfully if it's caught early enough," said Ms Nunn. "It's important that people go to the dentist regularly and report any symptoms to their GP or dentist without delay."