A disturbing 69% of fresh chickens on the supermarket shelves are infected with the campylobacter bacteria, according to the results of a survey conducted by the BBC's 4 x 4 television series.

Furthermore, researchers for the programme discovered that organic and free-range chickens were no less likely to be infected with the bacteria and 91% of the infected meat carried the most harmful strain of the bacteria.

The results of the survey of 100 fresh chickens, bought from Tesco, Sainsbury's, Asda, Safeway, Somerfield and Co-op, will be broadcast next Monday in a report by former Tory Health Minister Edwina Currie, whose time in office is generally associated with the health scare over salmonella in eggs.

Currie is reported to be "shocked and appalled" by the scale of the problem.

The campylobacter bacterium was found to be responsible for 54,994 of the 86,316 cases of food poisoning officially recorded in the UK in 1999. It can cause diarrhoea and severe stomach cramps, but scientists say that the bacteria can be killed by ensuring that the chicken is thoroughly cooked and consumers take care to wash their hands after dealing with the raw meat.