The husband of a retired teacher who disappeared from her 200-acre farm 14 months ago is no longer a formal suspect in her murder, police confirmed.

Kate Prout, 56, who was also a campaigner for milk payment prices, disappeared from £1.2 million Redhill Farm, in Redmarley D'Abitot, Gloucestershire on bonfire night 2007.

Police still believe Mrs Prout was murdered but have failed to find her body despite exhaustive searches of the property she shared with husband Adrian 46, who runs a pheasant shoot.

Civil engineer Mr Prout was arrested on suspicion of murder in November 2007 and again last February and was due to answer police bail again on Friday.

But today Gloucestershire police announced that Mr Prout's bail has been cancelled and he was no longer required to report to them. He has not been charged with any offence.

Acting Det Supt Neil Kelly, the senior investigating officer in the case, said today: "The investigation into Mrs Prout's disappearance and suspected death remains active and is continuing, and will do so for the foreseeable future."

Mrs Prout was reported missing from the farmhouse on November 10 2007.

She has not been seen since November 5 that year. Officers said again today that they still feel she was murdered.

At the height of the police probe there were in excess of 100 officers involved in both the search for Mrs Prout and in following up a number of different leads.

A 'small team' of staff are still working on the case and witnesses are still being sought.

Diane Bellamy, 48, from Bisley, Eric Woolley, 60, the landlord of the village's Rose and Crown pub, and a 43-year-old man from Lydney, were all arrested during the course of the investigation. None have been charged and all had their bail cancelled last year.

The search in the wake of her disappearance involved JCB diggers ploughing through wood chippings, and diving equipment.

The search was then moved to Dursley, 25 miles away from her home, where residents said they were questioned about water pipes laid at the time of her death.

Mrs Prout's brother, Richard Wakefield, 57, spoke at an early press conference of the family's "agony" at not knowing what had happened.

He said: "Discovering the truth, whatever that may be, will put us out of this agony of not knowing."

She was last heard of on the afternoon of November 5 when she made a phonecall to her brother's wife Linda, sounding untroubled and happy.

Mrs Prout spent 20 years as a primary school teacher before taking early retirement. At the time of her disappearance she was involved in a campaign to persuade the Government to increase milk payments to dairy farmers.

Mr Prout was approached by The Times newspaper in May to comment on the case. He spoke through the intercom saying: "No thank you, I have got nothing to say. No comment."