The research, published in the British Dental Journal, found that only half of those questioned had even heard of oral cancer, which covers cancers of the mouth, lip and tongue.

The BBC's Daniel Sandford: "The biggest causes of the cancer are tobacco and alcohol"

And though more knew or guessed that smoking was a prime risk factor for developing the disease, only one in five were aware that excessive alcohol drinking could also trigger it.

The survey has prompted the British Dental Association to call for the reduction of oral cancer to be included in government targets for cutting cancer.

It also believes a major publicity campaign would save lives.

The survey also showed that people had worryingly low awareness of colon cancer, another disease which relies on early detection to give sufferers a much improved chance of survival.

But 97% knew about lung cancer, 96% about skin cancer, 86% about cervical cancer and 78% about prostate cancer.

People in East Anglia and Scotland were the most aware, with 62% knowing about oral cancer - while those in London and North East England knew least.

One in two die

Oral cancer is one of the most dangerous cancers, as only one in two patients survive. Some 3,400 new cases occur in the UK each year and 1,600 die from the disease.

Dr Geoff Craig, chairman of the British Dental Association health and science policy group, said: "Early detection is the key to survival. It's important that doctors and pharmacists are aware of what to look for, as they often get asked about sores in the mouth."

He said that even experienced dentists might see only a handful of cases in their careers.

The warning signs of oral cancer are a sore that does not clear up, even after a few weeks, although most of these will prove harmless.

Although the main risk factor is smoking, another is drinking to excess - even going slightly above the government's recommended limits increases the risk.

Most men can drink three to four units a day without risk to health, most women two to three.

If men consistently drink four or more units a day, the health risks start to accumulate. The same goes for women who consistently drink three or more units a day.

One unit is equivalent to half a pint of normal strength beer, a glass of wine or a measure of spirits.

However, Dr Craig warned that people who both smoke and drink heavily are increasing the risk by as much as 40 times.