Colorectal cancer kills some 500,000 people every year. It is the second most common form of cancer in women and the third most common in men.

Some 80 per cent of these cancers start as colorectal polyps, which are relatively easy to spot and remove. But conventional colonoscopies are time-consuming, invasive and expensive, so various groups are looking for better ways to do the job.

One of the more promising options is colon capsule endoscopy. This involves a tiny digital camera, a light, a transmitter and a battery in a capsule which the patient swallows. As the capsule passes through the patient’s digestive system, it transmits images wirelessly to a recording device that the patient carries.