MURDER detectives have stepped up their search for a vital witness who could have been the last person to see a timeshare salesman alive, as the sixth anniversary of his death approaches.

The team has so far drawn a blank in tracking down the taxi driver who gave 37-year-old Kevin John Palmer, known as John, a lift shortly before his death during the early hours of March 13, 1999.

But their list of 600 possible drivers has now been whittled down to just 12.

Officers working on the murder inquiry, codenamed Operation Arkholme, have interviewed hundreds of drivers who were working in the area five years ago, but have not yet found the driver who took Mr Palmer on his last journey through Bishop's Waltham.

Det Sgt Jim Park said: "We're still looking for the taxi driver and it is proving difficult because of the passage of time.

"They are a transient population. We are down to the last 18 of a list of 600 or so, but sadly six of those have passed away so it's just a dozen to find now. Others have moved out of the area or out of the country which makes it a little bit more difficult.

"It's a significant line of inquiry that's taking a lot of time."

None of the drivers approached so far, who were registered to either Fareham, Eastleigh or Winchester councils, have been able to shed any new light on the investigation.

The witness is thought to have seen an argument between Mr Palmer and two other men and a woman after picking them up from the Abshot Hotel and Country Club in Titchfield Common at 1am.

After the dispute, the men got out of the vehicle and had a fight in Botley Road near Burridge Social Club and the Horse and Jockey pub.

Only two men got back into the car and Mr Palmer has never been seen again.

A murder inquiry was launched in 2003 during a search of a property belonging to jailed drug dealer John Howett in Hoe Road, Bishop's Waltham.

Officers, based at Southampton's Hulse Road police station are also carrying out inquiries overseas.

Mr Palmer had lived with his wife and daughter in Malaga for ten years before his disappearance.

If you can help, call the Operation Arkholme incident room on 0845 045 4545.