AN MP knew she was dying before she was appointed to Labour’s cabinet, it has been revealed.

Mo Mowlam, the MP for Redcar, east Cleveland for 14 years, was diagnosed with a malignant brain tumour months before Labour swept to power.

However, she told Tony Blair and her constituents it was benign, despite being told in 1996 that she would only live three years.

Until her death in 2005, only she, her husband, John Norton, and her doctor, Mark Glaser, knew the truth.

Dr Glaser has revealed the truth to Neil McKay, the author of the Channel 4 drama Mo, starring Julie Walters, which will be broadcast soon.

Speaking to The Observer newspaper, Dr Glaser said he felt a heavy sense of responsibility as she took up the post of Northern Ireland Secretary.

He said he urged her to tell the truth, but instead she committed herself to working on the peace process.

He said: “A frontal lobe tumour can cause disinhibition, behavioural disturbance and poor judgement.

“I told her to tell Blair, but she didn’t, she lied. I went the extra mile for her because she demanded it from me. I was trapped. It was a moral issue and a medical issue.

“She was doing this very important job, one that affected so many people’s lives, while she was ill, but she was also my patient and I owed her confidentiality.”

In 1999, she was replaced as Northern Ireland secretary by Peter Mandelson. She stood down as an MP in 2001.