More than 50 police officers today began searching remote farmland for the shotgun used to murder a Sussex millionaire.

Detectives hope the hunt by Surrey and Sussex officers - which could last up to four days - will provide a breakthrough in the five-year hunt for Richard Watson's killer.

Mr Watson, 55, was gunned down outside his five-bedroom farmhouse in East Grinstead in 1996.

Sussex Police today also announced a £15,000 reward for information leading to the arrest and conviction of the murderer.

Detective Chief Inspector Alex Wood, who is leading the inquiry, said an earlier £50,000 reward offered by family and friends of the millionaire had been withdrawn.

Officers today started searching at Nestledown Kennels at Blindley Heath, Surrey, about five miles from Mr Watson's home.

Six months after Mr Watson's death his wife, Linda, 43, and her 24-year-old daughter Amanda London-Williams were charged with murdering him with the aid of an unknown third person.

They were cleared of any involvement when the case was dropped just before they were due to go on trial at the Old Bailey.

The Watson murder inquiry was complicated by the businessman's worldwide business dealings - his firm had an annual turnover of £1.2 million - and by speculation he may have been killed by the Russian Mafia.