Andrew Rodgerson, 26, realised he faced owing £56,000 to a betting syndicate when he discovered he was too late to place the last piece of an accumulator on Conduit winning the last of a series of races.

So he used terror tactics to try to force the owners of the four-year-old colt to withdraw it from the £500,000 King George VI and Queen Elizabeth Stakes.

After getting the numbers of the Ballymacoll Stud from newspaper adverts, Rodgerson sent a string of email and text messages to the manager with one reading: "We don't believe you are taking the death of Conduit very seriously.

"We want the horse removed from the King George race this weekend. If you co-operate the horse will live. There are people in and around Newmarket ready and willing and there will also be people at Ascot on Saturday.''

But just two days before the race, Rodgerson was tracked down by detectives from two police forces who traced the messages to his bedroom 300 miles away in Balderstones, Rochdale, Greater Manchester, where he had set up a secret betting base.

It emerged he had become so busy at his regular job at a travel agency he forgot to complete the sequence of bets he had been asked to place – leaving his syndicate out of pocket. Conduit later romped home to victory.

During in the build up to the race, discussions were held between Sir Michael Stoute, who trained Conduit in Newmarket, and the integrity department of the British Horse Racing Authority to protect the horse's safety.

The BHA laid on increased security during the horse's journey to Ascot and while he was stabled at the racecourse.

On Monday, Rodgerson, 26, pleaded guilty to threatening to commit damage and was sentenced to 34 weeks in prison, suspended for two years, and was ordered to complete 240 hours of unpaid work. His not guilty plea to blackmail was accepted.

Bolton Crown Court was told the offence occurred in July when Conduit, which had already won £1 million in prize money, was favourite to win the King George VI and Queen Elizabeth Stakes.

Peter Reynolds, the manager of the Ballymacoll stud in Ireland where Conduit was bred, initially received a text message which said: "Dear Peter, we would just like to warn you should Conduit run in the King George then the horse will be killed."

Mr Reynolds then alerted the colt's trainer.

"Mr Reynolds was concerned that, after 37 years in the industry, he had never received any threatening messages before,'' said Duncan Wilcock, prosecuting.

Four hours later, Mr Reynolds got an email from a person who claimed he had heard a conversation in a bar in Manchester in which the horse Conduit was discussed and he claimed to have overheard that if it ran the horse would be killed.

Mr Reynolds waited five days before calling police but then got the personal email from Rodgerson warning of people "ready and willing'' to kill Conduit if he ran in the race.

"Mr Reynolds confirmed that the horse was a valuable asset and the business could be severely affected if they were influenced by those threats,'' said Mr Wilcock. "It was a very high-profile race and Conduit was the favourite to win.''

Rodgerson's mother later told police her son had had a gambling habit since he was 19 and kept large amounts of money in his bedroom.

Rodgerson – said to come from a religious family – said he often placed £300-400 bets each way on particular horses up to five times a day and built up his syndicate through friends at a cricket club.

Defending, Joseph Hart said: "He met local businessmen who liked to put money on the horses, and liked to make clever bets. He was put in touch with a gambling syndicate and there were people putting up much bigger sums of money.

"They told him when and where to put the bets on. They would bet on the best horses at the best races at the best odds.

"He was working in a travel agency but in the background he had the betting syndicate, which would insist on him putting bets on all through the day at specific times with specific companies and he forgot.

"He had a great big bet to put on Conduit on the accumulator and he forgot. He was too busy at work and didn't put it on at the right time with the right company.

"And he suddenly found himself realising that if Conduit won he would owe this syndicate around £55,000. He was utterly and completely terrified – he simply didn't know what to do. So he panicked and committed an unsophisticated and stupid crime.''

Mr Hart added: "Nothing that Andrew Rodgerson did stopped the horse running and he made no attempt to carry out the threat.

"The fact that this is a horse doesn't make it much different than a Ferrari – it would be different if it was a treasured family pet or a horse to which there was a very emotional attachment, but this was a horse which was an asset.

"These were people who found a naive young man who was willing to run around and put bets on for them."

Sentencing Judge Angela Nield said: "This was a foolish escapade. You allowed yourself to become embroiled in a world that was out of your own means and involved people far more sophisticated than you.

"But the syndicate cannot be blamed for what you ultimately did and your naivety led you into a much more serious course of action.

"These were serious threats against that horse that could very well have led to him being withdrawn from the race. The gravity of this offence lies in its potential impact upon the industry that clearly runs in a manner reliant upon the safety of its horses and riders and the integrity of those who appear within it.''

Conduit went on to win the race, netting more than £500,000 in prize money. In November, he won his second consecutive Breeders' Cup title before running fourth in the Japan Cup. He is now standing as a stallion in Japan.