Farmers were urged to "beef up" security measures after valuable satellite guidance systems were stolen from tractors at three Norfolk farms in two nights.
Norfolk police said crimes were reported at farms in Martham and Fleggburgh, near Great Yarmouth, and at East Ruston near Stalham.
A GPS receiver dome and computer screens were taken from a crop sprayer and tractor in Martham, near Great Yarmouth, between 6pm on April 28 and 7am on April 29.
Meanwhile, at around the same time, computer screens were taken from two tractors at a farm in nearby Fleggburgh.
The following night, thieves broke into four tractors on a farm in East Ruston near Stalham, between 6pm on April 29 and 6.15am on April 30 and stole three satellite screens and receivers.
This spate of crimes has prompted warnings of a "new wave" of tech thefts, following the spate of crimes last summer which forced some Norfolk farms to delay their harvest after GPS units were stolen from combine harvesters.
Patrick Verrell, a Norfolk agent for rural insurer NFU Mutual, said: “These criminals are well-organised and know what they are looking for - so it’s essential that farmers remove GPS kit when possible when it’s not in use and store it securely.
"It’s also well worth beefing up security in farm yards, machinery sheds and on tractors to make it harder for thieves to operate.”
Farming satellite systems can cost between £8,000 and £14,000.
But the loss of this equipment can also cause significant disruption to farm businesses said John Newton, Norfolk county adviser for the National Farmers' Union (NFU).
“This new wave of GPS thefts is very concerning," he said.
“We are urging farmers to protect their GPS equipment and take whatever steps they can to make it difficult for thieves to gain access."
PC Chris Shelley, rural crime officer for Norfolk police, said farmers should "remain vigilant", report any information to police, and mark their addresses or postcodes on their tools and equipment, to aid their recovery if stolen.
“Please paint or engrave your postcode on your tools and machinery because it can make a huge difference," he said.
"If your items are marked with a serial number, know your serial number and if you can possibly avoid it, please try not to leave valuable items in or on machinery."
- Anyone with information should contact Norfolk police on 101 quoting investigation number 36/28774/21 for the East Ruston crime, 36/28397/21 for Fleggburgh and 36/28352/21 for Martham.
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