Tractors have become the "hot model" for thieves because insurers fail to include engine and chassis numbers in insurance documents, warns private recovery company The Equipment Register.

Criminal gangs are believed to be behind the disappearance of scores of farm vehicles costing insurers around £400 million last year.

More than 100 tractors have vanished across southern England in the past 12 months.

Last week alone, four tractors from Hampshire and West Sussex and 18 horse boxes in Cornwall went missing. There was also a spate of tractors stolen from Kent before Christmas.

A top of the range John Deere tractor can cost as much as a Mercedes S280 - more than £40,000.

Mick Browne, senior plant investigator with TER, said: "One immediate improvement would be if insurers ensured they had details of the engine and chassis number of each make and model of tractor they insured."

Browne said the register, which he estimates only covers 20% of all stolen farm vehicles, should be bolstered by better information from insurers.

"Tractor theft is rife. 85% are stolen to order and shipped out of the country in containers to the Far East, Israel and Ireland. The other 15% are probably fraudulent claims."

Tim Price, of NFU Mutual, which has two-thirds of the farm insurance market, admitted it did not require farmers to note chassis and engine numbers.But he said that thieves rarely stole the whole tractor, preferring just to take the radio or battery which can be easily carried away.

"We are not against taking details of engine and chassis numbers per se, but it would add more administration to the procedure and costs at a time when farming is in a depression," he said.

But Browne added that chassis and engine numbers are only one part of the equation. He also called for the police to open up its data banks.

"Many stolen vehicles and equipment are not even notified to us or the police national computer," he said.

"What we need is a central mandate, legislation which insists this is done and the information properly circulated."

He added that overworked police and ports officials have little time to carry out extensive checks, which means many thefts go undetected.

£400,000 of plant is stolen
Insurance Times will publish the top 20 most valuable items stolen in the past month and registered with the The Equipment Register (TER) in every Claims Special. From December 19 to January 19, almost £400,000 of plant equipment and machinery was stolen.

Crane Kato Rochdale, Lancs £50,000
Fork Lift Hyster Slough, Berkshire £26,000
Telexcopic HND JCB Cheadle, Surrey £25,000
Mini Excavator Kubota Slough, Berkshire £19,500
Dumper Lifton Rathfriland, N. Ireland £18,250
Fork Lift Komatsu Slough, Berkshire £17,000
Fork Lift Komatsu Slough, Berkshire £17,000
Breaker Furukawa Barford, Wiltshire £17,000
Fork Lift Komatsu Slough Berkshire £17,000
Fork Lift Komatsu Slough, Berkshire £17,000
Mini Excavator Kubota Ansty, Midlands £16,500
Mini Excavator Yanmar Ansty, Midlands £16,500
Excavator Case Carshalton, Surrey £15,000
Excavator JCB Kingstone, Hereford £14,000
Mini Excavator Kubota Slough, Berkshire £10,000
Generator Genset Rugby, Midlands £9,995
Wood Chipper Entec St Albans, Herts £9,750
Dumper Benford Slough, Berkshire £8,000
Roller Benford Wigmore, Kent £7,500
Generator Harrington Daventry, Northants £6,900