WELL-known vet and mother-of-three Di Stapleton collapsed and died during an aerobics class in Embsay on Monday evening.

The cause of Mrs Stapleton's death is as yet unknown.

Mrs Stapleton, 39, lived at High Skibeden Farm on the outskirts of Skipton with her husband, George, a farmer, and three young children.

She worked at Settle's Dalehead veterinary Group where she was extremely popular and highly regarded by staff and clients.

There was widespread shock and sadness at the news of her death and tributes have poured in to both the vets and the family.

"She was my wife, the mother of my children and my best mate," her husband told the Herald.

"The world has stopped for me. This will always hurt.

"She had a smile that you couldn't touch, that didn't need any words. To me she was like wine - she got better and better the more and more we were together. She was just right.

"She was miss ultra busy. She would take the children to swimming, football and rugby, ran the house, was dedicated to her job and was doing a French A-level at night class."

Mrs Stapleton had attended aerobics classes in Embsay for about five months. She had been exercising on Monday, but had broken off to get a drink of water when she collapsed.

Two nurses - class members - gave heart massage and police arrived within minutes with a defibrillator. Soon after an ambulance crew took control, but they were unable to revive her.

Caroline Hewison, who has been running the classes at Embsay for 10 years, said everyone was shocked by the tragedy. "She was a very friendly person - a joy to have in the class. Our hearts go out to her family."

Mrs Hewison added that next Monday's classes would be cancelled as a mark of respect.

A North Yorkshire police spokesman said a post mortem examination had been held. However, the cause of death was not known at this time and further tests were being carried out.

Mrs Stapleton did not smoke, only drank socially and had no history of medical problems.

Her husband said: "She was a fit girl, it was literally a bolt out of the blue. She was full of life, whatever you asked her to do she would try her best to help anybody."

Diana Patricia Stapleton, ne Smith, was brought up at Kearby, near Wetherby, and attended Leeds Girls' High School.

She gained six grade As at A level and went to a veterinary college in Edinburgh, qualifying in 1987. Her first job was at Horncastle in Lincolnshire and in 1989 she joined the Dalehead Veterinary Group at Settle, living in the town.

She developed a particular interest in farm animal work, especially cattle fertility and had recently become involved with specialised embryo transfer work in pedigree cattle.

She met her husband, a farmer client of the practice, while treating one of his lambs and they married 11 years ago. they have three children - Thomas, nine, Anna, seven and Rebecca, two.

The family lived in Hellifield and more recently moved to High Skibeden where they farm dairy and beef cattle and sheep.

Neil Roberts, a partner at Dalehead, paid tribute to Mrs Stapleton.

He said: "She was universally liked and respected by work colleagues and clients. Nobody ever had a bad word to say about her. We have had a lot of people ringing in expressing their sadness and sympathy."

"The farmer clients really were her friends and during the foot and mouth outbreak in 2001 she would spend hours each day reassuring and advising clients.

"Di never shied away from the more physical aspects of the job - she would relish the challenge of a morning dehorning or calving a wild suckler cow," said Mr Roberts.

A funeral service will take place at the Priory Church, Bolton Abbey, next Friday, January 16, at 12.30pm and she will be buried at Embsay.