A wealthy businessman was battered to death and dumped in the sea by a man obsessed with buying his luxury boat, a court heard.

When detectives asked how £18,000-a-year train guard David MacBride hoped to pay for the 42ft motor cruiser he told them he had found £120,000 on a train to London.

MacBride, 44, of Bramber Close, Bognor, denies murdering 70-year-old widower Robert Saint, who disappeared on September 26 last year after he went to discuss a dud cheque used to pay for his boat The Sundowner.

The former timber yard manager never returned but his boat, on the market for £125,000, was found moored at Itchenor, close to where it had been docked at Birdham Pool, near Chichester.

His body was discovered by a fossil hunter ten days later on a beach on the Isle of Wight. Mr Saint had sustained fatal head injuries.

At Lewes Crown Court yesterday, Camden Pratt QC, prosecuting, said MacBride had been "obsessively keen to acquire The Sundowner", had lied about his ability to pay for it and had beaten Mr Saint to death with a blunt instrument.

Mr Pratt said Mr MacBride had made an offer for The Sundowner in August last year.

On September 24, a cheque for £119,000 was given to Mr Saint, who asked Barclays Bank in Chichester to cash it quickly, but it bounced.

MacBride allegedly agreed to meet Mr Saint on September 26.

The police arrested the train conductor the following day when Mr Saint, whose wife Pamela had died from a heart attack in 2001, did not return to his home in London Road, Steyning.

Mr Pratt said: "In police interview, when asked where he got the £119,000 for the boat, MacBride said he was on duty about four months earlier when he found £120,000 in a bag on a rack in a train on the way to Victoria."

Mr Pratt said MacBride claimed he gave Mr Saint the money in cash on the day he disappeared and dropped him off by boat at Portsmouth harbour. The money was said to be in used £50 notes in a small sports holdall.

Forensic scientists found traces of blood on a carpet in The Sundowner's galley on September 28 and arrested MacBride on suspicion of murder.

A shirt with MacBride's DNA and Mr Saint's blood was discovered in a box on the boat and more splatters of the pensioner's blood were spotted in its engine room.

Mr Saint's body was found with two plastic carrier bags tied around his head and a diving knife tied to his wrist. The head injuries indicated he had beaten with a heavy blunt instrument 16 times.

Mr Pratt said: "Blood spots are significant. They are the result of impact on to blood. You get splatter when blunt instruments impact on to wet skin.

"The more you hit wet blood, the more the splatter occurs.

"It looked as though Mr Saint had been struck with several blows."

Mr Pratt told the court how MacBride was earning £18,000 at the time of the alleged murder.

He had debts of £75,000, including a £56,000 mortgage, an £11,000 car loan and £10,000 debts to two building societies.

Mr Pratt said: "If he found £120,000 he might have paid off some of his debts, so there was no such money. I suggest he was obsessively keen to acquire The Sundowner."

The trial continues.