A respected showjumping trainer has been jailed for launching a terrifying stalking campaign against her former partner in which she burgled his home and threatened to burn it down.

Spurned Sarah Jones, 38, refused to accept Chris Cumming, 37, a successful trader in high-end horseboxes, wanted to end their five-year relationship.

So, in a plot straight from a Jilly Cooper novel, she set about trying to ruin his life by relentless intimidation in a case described by a judge as the worst of its type he had ever encountered.

For nine months Jones plagued Mr Cumming by burgling his home, bombarding him with hundreds of threatening messages, trying to burn down one of his valuable horseboxes, assaulting him on his own property and threatening to burn down his £600,000 farmhouse.

Mr Cumming described allowing Jones and her teenage daughters to move in with him at the expansive property in rural North Yorkshire as "the worst decision of my life."

He said: "Unless you have been through it you can't imagine the effect it has on your life when someone is determined to try to intimidate you and ruin your business.

"It has been the worst two years of my life. You don't want to see anyone go to prison but in this case she left the judge little choice.

"He said in court that it was the worst case of its type he had ever dealt with."

Jones was jailed last month for 18 months after she admitted harassment, burglary and theft on the day her trial was due to begin.

A charge of assaulting Mr Cumming was allowed to lie on file but he was granted a lifetime restraining order preventing her from going near him or his property.

The prison sentence caused shock in the Dales market town of Bedale, where Jones ran a high street livery and riding equipment store.

She is also well known in the showjumping world for producing and retailing top-rated jumpers and also worked in the racing world, driving horses for trainer Charlie Johnston, of one of the country's top stables, Johnston Racing.

Mr Cumming met Jones at horse shows, where he would promote his business, which has bases in Yorkshire and Aberdeenshire.

Jones was there to watch the horses she had trained compete, as well as supporting her eldest daughter, now 19, who is a talented showjumper.

Mr Cumming said: "We were together for five years. She and her girls moved in with me and at first things were good.

"But as time went on I became unhappy in the relationship and I had to ask them to leave. I bought my property myself on the back of my hard work building up my business, she had no claim to anything here.

"But she refused to leave and would not accept that the relationship was over.

"I had no choice but to involve the police and it was only at that point that she accepted she had to leave and when she did I had the locks changed.

"For me that was the end of it, but Sarah would not let it go and for between six and nine months she did everything she could to make my life a misery.

"On one occasion, when I was away, she broke into the house through a rear door. There was nothing here that she wanted. I think she just did it to show me that she could."

Jones was charged with stealing mail and a hoover but she also tried to destroy a horse box Mr Cumming had allowed her to use for equestrian events.

He managed to stop her from burning it to the ground after catching her throwing petrol around it.

Mr Cumming said: "She did assault me on one occasion. Even though it didn't cause any real injury, it stays in your head, the psychological burden is the worst part of it, I lived in constant anxiety about what she might do next.

"She even spoke to my customers, sending them messages with false allegations about me and my business. The effects of that are still ongoing, her actions have affected every part of my life.

"After our relationship ended she could easily have moved on with her life. She may not have had the lifestyle I was able to give her but she'd opened her shop and was doing well.

"Instead she was unable to move on and wasn't prepared to let me, it was the worst time of my life and I hope that going to prison has made her realise how serious it was and that she must now leave me alone to get on with my life."

Jones was interviewed in Equestrian Trade News when she opened her store and told how the community had rallied around - before her reputation was destroyed.

She told the magazine: "If we don't have something in stock, we will always try to get it in for customers and people appreciate that and will wait. Bedale is a very tight-knit community and they like to shop local."