Dr Ian Arnott is a leading specialist in ulcerative colitis. he is a consultant gastroenterologist at the Western General hospital in Edinburgh and the Royal College of Physicians’ associate director for the UK-wide, NHS-funded inflammatory bowel disease audit.

“Ulcerative colitis can be a very disabling condition and leaves people weak, tired, frustrated and lacking energy. It can change people’s lives completely. they can’t be very far from the toilet so aren’t able to go out very much. Patients tell me that when they go to a nearby town or city, they know exactly where every toilet is, because they often get very little warning about needing to go to the toilet. It can mean that people have accidents with their bowel motions. It’s an embarrassing condition – it’s a difficult subject to talk to people about.

“It is a serious inflammation of the large bowel, which is better-known as the colon. Where it should be pink, smooth and nice it becomes red, weepy and unhappy — it looks like you’ve taken the skin off your knee. The main symptoms are diarrhoea, blood in stools, stomach pains and feeling rotten. It goes up and down. You will have good periods of remission when you feel normal – that can be a month or even a few years – and bad periods when you feel dreadful and can be forced to go to the toilet six, eight or 10 times a day around the clock, including two or three times a night. if you can imagine having food poisoning and that going on for weeks on end, rather than days, that’s what it’s like.

“It’s quite a common condition. if you take ulcerative colitis together with Crohn’s disease, which has similar symptoms, they are known together as inflammatory bowel disease (IBD). one in 200 people in the UK develop IBD, so around 300,000 have that. Young people aged between 10 and 40 get it.

“It’s not a curable condition unless you have an operation. With surgery you take the colon out completely. People often need an external bag to collect their faeces, though some people get an internal pouch which lets them go to the toilet normally. so you wouldn’t have surgery unless you had to. However, one-third of patients end up having an operation to remove their colon at some point in their lives.

“The cause of colitis is unknown. It’s genetic to some extent, but less than with Crohn’s disease, but something unknown in the environment comes along and sets it off. It could be food, atmospheric pollution or stress – no one really knows what it is. It could be all of them.”