IT causes crippling pain for six unlucky people in every 100, and in the worst cases it can even kill.

But the human appendix is one of life's mysteries - because it has absolutely no purpose.

It is a worm-like pouch attached to the large bowel and if it becomes inflamed - for reasons not even doctors can explain - it normally has to be removed.

Dr David Fair, a GP at Jorvik Medical Practice, in York, said he was just as baffled by the appendix as anyone.

He said: "There is no real reason why it is there. It has got some sort of role in detecting foreign bodies in the food, but it is not essential, and you still function completely normally without it."

Acute appendicitis can strike anybody at any time - though it is most common in young people under the age of 25.

Dr Fair said it was important for people to be aware of the symptoms, because it was easy to confuse the condition with stomach troubles.

He said: "The pain generally starts around the tummy button, but within about 12 hours it tends to move towards the right iliac fossa.

"This is to the right, just below the tummy button, towards the pelvic bone.

"It's a crampy pain, that comes and goes and gradually becomes more continuous.

"Quite often bowel movements stop and you start to feel feverish with a temperature. You will normally also be sick."

He said doctors diagnosed accute appendicitis by feeling and listening to the stomach.

He said: "Often the stomach muscles become rigid when you have appendicitis, and also the squirty sounds of your bowel stop. It temporarily becomes silent."

In the 1930s, before the discovery of antibiotics, improved anaesthetics and better surgical standards, the national death rate from appendicitis was ten per cent.

"If your appendix ruptured, then you would usually die a horrible and excruciating death," said Dr Fair. "But that's unusual today."

He also said it was now possible to take out the appendix through keyhole surgery, which means a much quicker recovery and a smaller scar.

'Bent double' by the pain

Gavin Aitchison, the political reporter at The Press, has recently recovered from acute appendicitis.

His troubles began in the early hours of August 20, when he woke up experiencing sharp pains in the stomach area.

Thinking food might help settle the pains, he decided to tuck into a bowl of cereal - but was promptly sick.

Unable to sleep, the dedicated reporter eventually got up and made his way to work at The Press's Walmgate offices.

He said: "Within an hour I felt unbelievable pain and was bent double over my desk.

"I had no idea what it was, although I didn't think it was food poisoning because I'd had gastroenteritis in March and it didn't feel anything like that."

By early afternoon, Gavin's condition had deteriorated and he decided to seek help from a doctor.

He said: "The doctor thought it was probably appendicitis and by 8.30pm I was in surgery.

"It all happened so quickly. I was fine when I went to bed the previous night."

Gavin, who is 25, spent two nights in hospital, and it was a further two-and-a-half weeks before he was able to return to work.