Driving Law
Last reviewed: 23 July 2026
TL;DR
Mobile speed camera vans use laser based devices that can measure a vehicle's speed from up to 1 mile away in clear line of sight conditions, although typical enforcement happens within a few hundred metres. A recorded offence normally brings a £100 fixed penalty and 3 points, or a course offer for lower speeds.
How mobile enforcement compares
| |||||||||||
Source: GOV.UK, Speeding penalties
KEY FACTS
|
How far away can a mobile speed camera catch a driver?
Police forces state the laser devices in enforcement vans can measure speed from up to 1 mile away in clear line of sight, though typical operational range is a few hundred metres.
The technology is laser based: the operator places the aiming point on a vehicle and the device returns a speed reading in a fraction of a second from the reflected pulses. Range in practice is limited by line of sight, weather and the need to identify the vehicle and its plate clearly enough to prosecute, which is why most recorded offences happen well inside the theoretical maximum. Bends, crests and traffic between the van and the target all shorten effective range.
Distance also cuts the other way: a driver who only spots the van as they pass it may have been measured long before. Braking on sighting a van therefore changes nothing about a reading already taken, and harsh braking near enforcement sites is itself a hazard the deployment guidance tries to avoid by siting vans visibly.
Do mobile cameras work at night and in both directions?
Yes. The devices work in darkness and can record vehicles approaching or moving away, including capturing front and rear plates.
Infrared illumination and the camera systems paired with the laser mean darkness is no protection, and the equipment reads speed on receding vehicles as readily as approaching ones. Motorcycles, which carry only a rear plate, are typically captured from behind. Vans parked on bridges, laybys and junction mouths are all lawful deployment positions, and there is no legal requirement for warning signs before a mobile enforcement site, although many forces use them as policy.
Operators log each session, and the calibration records of the device form part of the evidence chain. Devices are required to hold Home Office type approval and to be checked at prescribed intervals, which is the technical backbone that makes readings admissible.
What happens after being caught by a mobile camera?
The registered keeper receives a Notice of Intended Prosecution within 14 days, followed by a fixed penalty of £100 and 3 points, a course offer, or court proceedings depending on the speed.
The NIP asks the keeper to identify the driver, and failing to respond within 28 days is the separate MS90 offence carrying 6 points, usually a worse outcome than the speeding itself. Once the driver is identified, the disposal follows the speed: no action or a course offer in the lower bands, the standard £100 and 3 points fixed penalty in the middle, and prosecution for the highest speeds, where sentencing guidelines start at 6 points or disqualification and an income linked fine.
The 14 day NIP deadline applies to the first notice to the registered keeper at the DVLA address, which is one more reason an out of date V5C address is expensive: the notice is validly served at the recorded address even if the keeper never sees it, and the prosecution for failing to identify the driver proceeds regardless.
Is there a tolerance before a mobile camera records an offence?
Enforcement thresholds commonly follow national guidance of 10 percent plus 2 mph over the limit, but the tolerance is guidance rather than law, and any speed over the limit is technically an offence.
The 10 percent plus 2 figure exists to keep enforcement focused on meaningful excess rather than speedometer margins, and it feeds the course eligibility bands as well. Forces are not obliged to apply it, and periodic force level trials of tighter thresholds have been reported over the years, so the only reliable rule is the limit itself. Vehicle speedometers are required to read at or above true speed, never below, which gives most drivers a small real world margin they are usually unaware of.
Where a driver believes a reading is wrong, the route is to reject the fixed penalty and contest in court, where the device calibration records and operator evidence are tested. Successful challenges are rare and the costs risk of losing at trial is real, which is why disputes tend to focus on procedural failures such as NIP service rather than the reading itself.
RELATED GUIDES |
DISCLAIMER This guide is for general information only and is not legal or financial advice. Rules, rates and processes are set by DVLA, DVSA and HM Treasury and can change. Always confirm current requirements on GOV.UK before acting. |
Frequently asked questions
Can a mobile speed camera catch a driver from 1 mile away?
In clear line of sight the laser devices can measure speed at distances up to around 1 mile, per police force statements, though most enforcement readings are taken within a few hundred metres.
Do mobile speed vans have to be visible?
No law requires vans to be visible or signed. Many forces choose visible deployment as policy, but a concealed position does not invalidate a reading.
How quickly must a speeding notice arrive?
A Notice of Intended Prosecution must normally be served on the registered keeper within 14 days of the offence, sent to the address on the V5C.
Does slowing down after seeing the van help?
No. The reading is typically taken before the driver sees the van, and braking afterwards has no effect on a speed already recorded.
Do mobile cameras catch motorbikes?
Yes. Motorcycles are usually captured from behind using the rear plate, and the laser devices read receding vehicles as readily as approaching ones.
SOURCES |
