A car parked on the drive is part of the home’s security perimeter, and the keys inside the house are the weak point. Vehicles with contactless “smart” keys can be stolen without the key ever leaving the hallway. This article summarises Secured by Design’s guidance on relay theft, Home Office statements about signal-manipulation devices, and the text of section 149 of the Crime and Policing Act 2026, which creates offences relating to such devices across the United Kingdom. It is general information, not legal advice or a guarantee that any measure will prevent a theft.
How relay theft works, according to Secured by Design
Secured by Design, the police-backed crime prevention initiative, says vehicles fitted with a smart or passive key are susceptible to relay theft. Criminals normally work in pairs and use cloning devices able to grab the signal from the smart key so that the car appears to detect the key nearby. The process can take as little as 60 seconds, and for safety reasons the engine will not cut out when the key goes out of range. Secured by Design says vehicles are most vulnerable overnight, particularly on a driveway or directly outside a home, where most of these thefts occur.
The practical advice
Secured by Design lists six measures for owners:
- Use a pouch. Store keys in a security pouch, described as a Faraday bag or RFID signal shield, when not in use at home, out and about or on holiday. The pouch is meant to stop the signal being captured.
- Do not leave keys by the door. Fishing for vehicle keys through the letterbox is described as a prominent method of stealing them, and signals are easier to grab when keys are near the front door.
- Disable the fob where possible. Some fobs can be switched off, so the vehicle manual or dealer should be consulted.
- Fit a tracker. Trackers can increase the chance of recovery after a theft.
- Use locks or clamps. Steering wheel locks and wheel clamps are described as a deterrent because thieves prefer to avoid anything that slows their getaway.
- Consider CCTV to view the garden, having first read the Information Commissioner’s Office advice on domestic CCTV systems.
Secured by Design also advises anyone buying a new car to speak to the dealer, because manufacturers and industry bodies have been working against relay theft for years.
How common signal manipulation is
A Home Office announcement dated 24 February 2025 cited the 2022 to 2023 Crime Survey for England and Wales, in which an offender manipulated a signal from a remote locking device in 40% of vehicle thefts in England and Wales. It also cited 732,000 incidents of vehicle-related theft in the year ending September 2024, and the Metropolitan Police Service’s estimate that signal jammers are used in approximately 60% of vehicle theft in London. Those figures describe England and Wales, not the whole UK, and the Metropolitan Police figure is an estimate for London.
The new offence
Before the Act, the Government’s factsheet says, these devices were not in themselves illegal to possess. Offenders could be charged with going equipped to commit theft under section 5 of the Theft Act 1968 or with conspiracy, but the prosecution had to prove the offender’s intention to steal a vehicle. Section 149 of the Crime and Policing Act 2026, headed “Electronic devices for use in vehicle offences” and marked as extending to the UK, changes that focus:
- It is an offence to possess an electronic device in circumstances that give rise to a reasonable suspicion that it will be used in connection with a relevant offence.
- It is an offence to import, make, adapt, supply or offer to supply such a device in the same circumstances.
- It is a defence to show the person did not intend or suspect the device would be used in connection with a relevant offence.
- The court may assume a person possessed a device found on premises they occupy or habitually use, unless they show they did not know of it or had no control over it.
A “relevant offence” is defined separately for each nation: theft of a conveyance or anything in it, or taking a vehicle without authority, under the Theft Act 1968 in England and Wales and the Theft Act (Northern Ireland) 1969 in Northern Ireland, and the equivalent theft or taking offences in Scotland.
Penalties and legitimate devices
On conviction on indictment the maximum is five years’ imprisonment, a fine, or both. On summary conviction it is the general limit in a magistrates’ court in England and Wales, 12 months or a fine in Scotland and six months or a fine in Northern Ireland. The Government’s factsheet says some signal devices are legitimate, such as signal repeaters approved for use by Ofcom to boost weak mobile signals, and that people with a valid use should be able to show it. The site’s separate article on signal jammers and the home covers the older offences about jamming Wi-Fi and cameras.
Is the offence in force?
Legislation.gov.uk shows section 149 as not in force at Royal Assent, with commencement governed by section 255(1) of the Act, and it displays the section as a prospective version until a commencement order is applied. The offences therefore apply from the date they are brought into force.
The bottom line
Relay theft is described by Secured by Design as a driveway-and-doorway problem: keep keys in a signal-blocking pouch, away from the front door and letterbox, consider disabling the fob, and add a physical lock or tracker. The Crime and Policing Act 2026 will add UK-wide offences for possessing or supplying devices used in vehicle theft, with a five-year maximum on indictment, but they apply only once commenced.