Ulcerative colitis is a long-term condition where the colon and rectum become inflamed.

Along with Crohn’s disease, it falls under the banner of inflammatory bowel disease (IBD).

It is estimated that one in every 420 people living in the UK have ulcerative colitis - or around 146,000 people.

According to the NHS, it happens when small ulcers develop on the colon’s lining, causing them to bleed and produce pus.

It is considered to be an autoimmune condition - like rheumatoid arthritis and multiple sclerosis - because it is triggered when the immune system starts attacking healthy tissue.

Scientists believe the immune system mistakes harmless bacteria inside the colon for a threat and attacks colon tissue.

Why the immune system does this remains unknown.

The condition can develop in people of any age, according to the NHS, but most sufferers are between 15 and 25 years old.

These are the three main signs of the condition, according to the NHS.

- Recurring diarrhoea, which may contain blood, mucus or pus

- Abdominal (tummy) pain

- Needing to empty your bowels frequently

Additionally, sufferers may experience extreme tiredness, loss of appetite and weight loss.

Symptoms will vary depending on the extent and severity of inflammation in the rectum and colon.

Signs of ulcerative colitis may not happen all the time. People can go weeks or months without a flare-up.

However, if flare-ups do happen, they can be particularly bad.

In these cases ulcerative colitis can affect other areas of the body, such as by triggering mouth ulcers, red eyes and painful joints.

What’s more, shortness of breath, an irregular heartbeat and a high temperature could be other indicators of a severe episode.

The NHS explain that the condition is usually treated with medications at home. Although sometimes surgery is required.

IBD should not be confused with irritable bowel syndrome (IBS) which requires different treatment.