It will take pictures three times a second and transmit them to screens here in the Science Museum via sensors on my body.

So Michael, ready when you are.

OK.

You pop that into your mouth.

Food can take up to three days to travel through the gut, but last night I drank four litres of laxative, so I'm expecting my camera to travel rather more quickly than that.

Anytime you swallow food, the esophagus will be able to tell that there's a force on its muscles to try and push it further down.

So this black hole here, soon you'll see the capsule passing into the stomach.

Here it goes.

Ooh, there it goes.

Down here, it's a cavernous alien landscape.

And you can see some white blobs of porridge I ate for breakfast.

I'm going to test the powers of my digestive system by feeding it a substantial meal with a big meal of steak and chips inside me.

My stomach has expanded.

The average human stomach can expand from the size of a small apple when it's empty to about two litres when full.

The camera has now been travelling inside me for over four hours and embarked on the longest part of its journey.

The tight folds on the wall of the small intestine are mixing and churning my mushed-up food in a corkscrew motion.

Digestive enzymes from the pancreas and gallbladder flood the area.

These enzymes induce chemical reactions which break the food down into nutrients that my body can readily absorb.

So on the folds here, on the folds of the small bowel, you can see the finger-like projections of the small bowel lining, which are called villi, and what they do is to increase the surface area of the small bowel hugely.

What sort of surface area are you talking about?

About a tennis court size, if you strip it all out, so it's really huge.

There's a huge amount of work that goes on in there.

And all this work requires a healthy blood supply.

As I'm lying here digesting my steak and chips, a third of my body's blood is being diverted away from my extremities and towards the action in my guts.

And as this blood rushes through the vessels in the wall of my small intestine, it's picking up digested nutrients and transporting them all over my body.

It's been almost nine hours since I swallowed the camera and began life as a museum exhibit.

We're at the outer reaches of this alien world.

The large intestine, or colon.

The camera has travelled over five metres through my guts.

You can see that the lining of the colon is very much flatter and whiter than the small bowel, and you can see the little blood vessels running through very, very clearly in colon.

Through the flatter, wider surfaces of the colon, water is being drawn out from what we have some slightly more formed material in there.

That's Mark's polite way of saying that what we're looking at is faeces.