British 2012 Olympic gold medal-winning showjumper Ben Maher is being sued for about £700,000 amid claims he made secret profits from horse deals. Maher is expected to deny the allegations and defend a High Court action brought by long-time backers Mike and Emma Phillips. They also seek the sale of Tripple X, the horse he rode to team gold. "It is all now in the hands of the court. It's a very sad end to a highly successful partnership," said Emma. Maher, 30, from Essex, has many fans in showjumping and has spent much of the year as the world's number one rider. Two claims from the couple - who run Quainton Stud in Aylesbury, Buckinghamshire - have been lodged at the Chancery Division of the High Court and outline the allegations against Maher. They say he acted as agents for them in the buying and selling of horses, but secretly made money on some deals by giving them incorrect details of the prices paid. He is alleged to have told the Phillips one of their horses, Tackeray, had been sold to a buyer in the United States for $500,000 rather than what they say is the actual sum of $850,000. "Mr Maher thereby made a secret profit of $350,000 of which Mr Maher is accountable and to which Quainton Stud is entitled," says the court document. It describes an invoice of $50,000 for third party commission on the deal as "a sham". The showjumper is accused of making a secret profit or benefit on five other horses: Quainton Quirifino (10,000 euros), Awanti (50,000 euros), Vigolo (152,000 euros), Robin Hood (£80,000) and Wonderboy (£222,496). The Phillips say they have worked with the rider since 2005 when he was aged 22 and treated him "as one of the family". Maher is said to have sold a half share in his Olympic horse Tripple X to them, and they enjoyed his success as part of the British victory in 2012. But the relationship broke down earlier this year, and as part of their second civil action, the couple want to see Tripple X sold. "We did all we could to provide the conditions that led to Ben's fantastic success at the Olympics last year and now feel broken-hearted," said Emma. It is understood the practice of a jockey riding, training and acting as bloodstock agent is not unusual, and the case could have wider ramifications in equestrian sport. "We love the sport. We adore our horses - but, in truth, we've become totally disillusioned," added Emma. Maher has enjoyed a rise through showjumping's rankings and his successful 2013 has included being part of the British team that won the Dublin round of the Nations Cup. He was also victorious in the King George V Gold Cup at Hickstead. He won team gold at London 2012 alongside Brash and Nick Skelton, then 54, and Peter Charles, 52. © BBC