DETECTIVES are investigating a North-East father and son who have gone missing from their business along with hundreds of thousands of pounds of customers' cash.

Police in Darlington say they have been deluged with complaints about Just Trucks, which was run by Gary Upson and his son, Ryan.

The pair have not been seen for more than a fortnight at their premises in Banks Road, Darlington, where they converted lorries into customised horse boxes.

Detective Sergeant Jeff Pow told The Northern Echo: "We have had contact from quite a large number of people regarding monies owed by Just Trucks to them or vehicles that haven't materialised.

"I have just started the investigation and I'm struggling to cope with the number of people who are ringing up. It is virtually every second phone call.

"We are taking details of the persons and what they claim they are owed. One of my staff has been to the premises but it's locked up."

The Northern Echo has spoken to customers who claim to be owed thousands of pounds from the Upsons.

They say they gave deposits to the pair, usually for half the value of the truck they were buying.

Angela Greensitt, from Wakefield, gave the Upsons a £10,000 deposit on a horse box. She said: "They have just been taking money from people and not giving them anything in return. It's sickening."

Robin Raine, managing director of Pro-Truck Commercial Services, which leased the premises in Banks Road to the Upsons, said at least 30 customers had contacted him with complaints about the pair since before Christmas.

He said the Upsons had leased the site since 2002 and had always paid their rent up until about March this year.

"We have been watching them since Christmas time and been quite concerned because of customers ringing us up and being very irate," he said.

"What I want to make clear is that Pro-Truck has no connection whatsoever with Just Trucks and we are still trading."

The Upsons' business partner, Karen Winks, who did administration work for Just Trucks, said she was bewildered by their disappearance.

"I'm very much in the dark," she said. "All I know is that they have gone and I don't know where. They have left me in an awful predicament."

High Court officials are seeking the Upsons to issue them with a writ following a county court judgement.

Trading standards officers in West Yorkshire and Darlington said they had received complaints about Just Trucks and had advised customers to contact solicitors.

Just Trucks advertises itself as a limited company but Companies House has confirmed that it is not one.

"We take a dim view of any company purporting to be limited, if it is not," said a spokesman. "We ask anyone with a complaint about the firm falsely advertising itself to contact us."

Just Trucks has had £100,000 worth of court judgements made against it since the start of last year and has a maximum risk credit rating.

The Upsons could not be contacted by The Northern Echo last night for comment.

But when we spoke to them last month about complaints, they said customers needed to be patient, as wagon conversions took time to complete.

"We are a bit late," said Mr Upson senior. "We hold our hands up to that. We give an approximate date but never give an exact date. We have lots of customers who are happy with what we do but some of them won't leave you alone to finish the job."

* Anyone with information or a complaint about the Upsons is asked to call Det Sgt Pow or PC Mark O'Brien on (01325) 467681.

* Did you work for Just Trucks or does the company owe you money? If so, call Sam Strangeways at The Northern Echo on (01325) 505022.