Cancer Research UK is encouraging people to exercise to reduce the risk of contracting cancer.

In its latest campaign, the charity is recommending that people take part in moderate exercise for 30 minutes, five times a week, in an effort to stay in shape.

The five-year Reduce the Risk campaign will target thousands of GPs' surgeries, health promotion units, hospitals and outpatient departments with leaflets and posters covering its key messages.

Information will be distributed to local authority leisure centres, swimming pools and shopping centres.

The charity will produce guidance leaflets on healthy eating and distribute Reduce the Risk messages to almost half a million participants in Cancer Research UK's Race for Life fundraising event this summer.

The charity said that half of all cancers could be prevented by changes to lifestyle, so in addition to fitness, the campaign will also encourage people to stop smoking, eat and drink healthily, protect themselves from the sun and become more aware of their bodies so they can quickly spot any changes.

The campaign follows research commissioned by the charity, which showed an alarming ignorance about cancer and how to reduce the risk of the disease, which is Britain's biggest killer.

The results of the survey showed there is confusion over what increases the risk of cancer. Of the 4,000 people questioned two thirds (66 per cent) were unaware that being overweight or obese increases the risk of some cancers. Almost exactly the same number (67 per cent) did not know that a diet low in fruit and vegetables could increase their chance of cancer.

Only one third (34 per cent) mentioned drinking less alcohol as a way of reducing risk and around 75 per cent of those questioned were ignorant of the cancer risks posed by taking HRT or having many sexual partners.

“There is no magic pill to prevent us getting the disease but there are many things we can all do in our daily lives to improve our chances of avoiding it,” said Cancer Research UK’s chief executive, Professor Alex Markham.

“It’s important for people to realise that being a healthy weight and eating a properly balanced diet with plenty of fruit and vegetables can really make a difference to their cancer risk, as can maintaining an active lifestyle and taking advantage of screening programmes.”