More than 20 million people wouldn't change their lifestyle even if they knew someone with mouth cancer, according to new research.

More than three in 10 (31%) said they wouldn't change their lifestyle, which includes tobacco use, drinking alcohol to excess, poor diet and the human papillomavirus (HPV), often transmitted via oral sex.

The survey also revealed one in four (25%) believe they are at risk from mouth cancer, a disease that claims almost 2,500 lives a year - one every four hours - in the UK.

The statistics reinforce the scale of the lack of awareness around mouth cancer. Throughout November Mouth Cancer Action Month, run by the British Dental Health Foundation, sponsored by Denplan and supported by Dentists' Provident and the Association of Dental Groups (ADG), aims to raise awareness of the risks and symptoms of mouth cancer.

Cases of mouth cancer have increased by 50% since the turn of the millennium, so ulcers that do not heal within three weeks, red and white patches and unusual lumps or swellings in the mouth should not be ignored, as they are all potential warning signs.

Regular check-ups can be vital in spotting early life-saving signs of this disease. If it is caught during the early stages survival rates can reach as high as 90 per cent. Without early detection, the Foundation, alongside fellow mouth cancer campaigners the Mouth Cancer Foundation, warn half of people will die.

Chief Executive of the British Dental Health Foundation, Dr Nigel Carter OBE, stressed the importance of making the right lifestyle choices.

Dr Carter said: "The choices we make have a significant bearing on our health. Your risk, or otherwise, is very much dependent on your lifestyle. The number of people who wouldn't change their ways despite knowing the lifestyle could result in developing mouth cancer is flabbergasting.

"Mouth cancer affects the way you speak, the foods you can eat, the way you look and your quality of life. Survivors often recall how difficult the basic everyday functions we take for granted become. Hopefully their stories can prompt people to make a change and reduce their risk."

Christine Gundry, 29 from Glasgow, can explain first-hand how mouth cancer can change your life. She said: "My operation was almost 12 hours long. The tumour was removed along with most of the floor of my mouth, half my tongue, some teeth and a small shaving of jawbone. But it took another operation, in which the surgeons de-bulked my new tongue and floor of my mouth (reducing their size), before I felt any big improvement in speech or eating. This was followed by another minor operation to further de-bulk my tongue and implant new teeth.

"Recently I have had another operation. The surgeon removed some more tongue, gum and completed the second part of the implant which means talking and eating is painful at the moment. It has been almost two years since my diagnosis, and only now am I nearly recovered. Mouth cancer changes lives."