NORTH Wiltshire MP James Gray has admitted his marriage is over after having a 19-month affair.

The MP told his wife Sarah about his relationship with mother-of-three Philippa Mayo three weeks ago.

Mrs Gray, 51, who this year won her fight against breast cancer, is moving out of the family home in Slaughterford, near Chippenham. The couple have been married for 26 years and have three children.

Mr Gray, 52, said: "I deeply regret the pain and suffering I have caused my family and the disappointment it may have brought to my constituents.'' Mr Gray said that his future is with countryside campaigner Mrs Mayo, 44, and that she intends to move to north Wiltshire.

"I hope that in the fullness of time we will be married,'' he said.

"I will not be resigning nor is there any possible reason why I should do so. I have been elected to represent the interests of the people on north Wiltshire is Parliament and hold the Government to account and I hope that I do a reasonable job of doing both things and I will continue to have the opportunity to do so.

"The sadness of what is happening in my private life should not affect my ability to carry out my duties precisely as before. "I hope that despite all of this people of north Wiltshire are happy for me to continue to represent them for another 20 years. "I am not proud of myself but I hope that now we can plan our futures,'' he said.

A close friend of Mrs Gray, who is away on holiday, said she had had no inkling of the affair.

"She was not aware the marriage was breaking down until she found out about the affair three weeks ago,'' the source said. Mrs Gray was diagnosed with cancer in April 2005, but has been in remission since February, after a lumpectomy, chemotherapy and an operation to remove lymph glands.

Mrs Mayo met Mr Gray in February 2005. They began seeing each other shortly afterwards. Last Christmas Mrs Mayo's husband Rupert, a London barrister, became suspicious that she was seeing Mr Gray and some weeks later confronted her. She admitted the affair but said it was over.

His suspicions continued however and early this summer he confronted her again. She admitted the affair had continued and Mr Mayo moved out of their home in Leicestershire. Their children are 14, 12 and nine.

Mr Mayo is said by friends to be heartbroken and has written to Mr Gray, telling him he is not fit for office.

Mr Gray has told the North Wiltshire Conservative Association and Tory party chiefs of his marriage break-up and the reasons for it and they are standing by him, although they have only known about the affair for the last week.

Roger Miller, chairman of the North Wiltshire Conservative Association, said: "I was surprised. I heard her name about two months ago as a friend of James. I knew they were close friends."

Mr Miller, who has chaired the association since March, said so far there had been no calls for Mr Gray to resign as the area's MP and that the executive committee, which is responsible for selecting and adopting MPs, were backing him. "This is a purely private matter," he said.

Mr Gray was elected MP for north Wiltshire in 1997, and has held the seat successfully at the two General Elections since. His increased majority last may was seen as an indication of how well he is regarded locally as a constituency MP.

He has had roles in the Shadow Cabinet, being front bench spokesman on education and employment in 1999, Opposition Whip in 2000, spokesman on defence in 2001 and on transport and the environment in 2003. In 2005 he was appointed Shadow Secretary of State for Scotland, but resigned after a few weeks.

He is a fervent supporter of fox-hunting, and campaigned against the Hunting Bill which outlawed the sport. mrs Mayo, whose family home in leicestershire is in prime hunting country, is also a keen huntswoman.