The pill's view of the stomach and intestine

It radios the images from inside the body to a portable recorder strapped to the patient's waist.

Natural contractions

The compactness of the new system means that the patient can avoid the inconvenience of a hospital stay.

"The main advantage is that it is very small and completely painless for the patients," Professor Paul Swain, from the Royal London Hospital, Whitechapel, told BBC News Online. "Once they have swallowed the pill, they don't feel it - and they can go home or go to work.

"The belt and the receiver is then sent into the hospital where it is plugged into a computer. A doctor can then examine the images to see if there are any problems."

The team would like to get more control over the movement of the capsule

The capsule is forced through the intestinal tract by natural contractions (peristalsis) and eventually expelled.

Quality images

In the day it takes to go through a patient's system, the capsule will provide up to six hours of high quality images from the stomach, small bowel and mouth of the large intestine.

The journal Nature reports that the capsule has been tested on 10 volunteers but it must complete clinical trials before being made available commercially. Professor Swain said he hoped this would happen within the next 12 months.

Eventually, further refinements and add-on technologies would make the capsule a "core device" in diagnostic medicine, he said.

"Maybe we could make it move around like a little robot and travel up and down the gut. Maybe we could make it sample tissues or send out signals that imply what is going on inside the body - and perhaps in the future we could even treat people from the inside."

It is more comfortable than standard endoscopes