Speed cameras in the UK: types and how they work
The UK uses several types of speed camera, from the familiar rear-facing Gatso to average-speed cameras that track you over a distance and HADECS cameras on smart motorways. Newer AI cameras can detect far more than speed. If one catches you, the registered keeper receives a notice within 14 days.
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Types of speed camera in the UK
Speed cameras fall into a few broad families. Fixed cameras sit in one spot and catch your speed at a single point. Average-speed cameras work in pairs or networks over a stretch of road. Mobile cameras are operated from vans or handheld devices at varying locations. Newer AI cameras add the ability to spot other offences entirely.
Knowing which is which matters because they catch you in different ways. A single-point camera measures one instant, while an average-speed system judges you over a much longer distance, so slowing only at the camera achieves nothing.
Average-speed cameras operate on some of the UK's most congested motorways - our guide to the UK's biggest motorways covers where each major route runs, how long it is, and what makes each one distinct.
How does a Gatso camera work?
The Gatso is the classic yellow box camera, usually rear-facing so the flash does not dazzle drivers. It uses radar to measure your speed and takes photographs as you pass. White lines painted on the road behind it provide a secondary check of the distance you travelled between frames.
Because it captures a single point, a Gatso records your speed at the moment you pass it. It is rear-facing to photograph the number plate of a car that has already gone by, which is why the flash often appears behind you.
Speed awareness courses are offered as an alternative to a fixed penalty notice when triggered by a speed camera - the speed awareness course - how it works and when it is offered covers the eligibility criteria, the cost, what the day involves, and whether it affects your insurance premium.
What are average speed cameras and how do they work?
Average-speed cameras, often seen on motorway roadworks and accident-prone routes, measure how long you take to travel between two points. They photograph your number plate at the entry camera and again at the exit camera, then calculate your average speed over the distance.
This design closes the loophole of braking only at the camera. If your average speed across the whole stretch is over the limit, you are caught, even if you were within the limit at each individual camera. They run continuously, day and night.
The enforcement network sits against a backdrop of stable casualty data - annual UK road accident statistics show 1,602 deaths and 128,272 total casualties in 2024, with speeding recorded as a factor in nearly a third of fatal crashes.
What are HADECS cameras on smart motorways?
HADECS, the Highways Agency Digital Enforcement Camera System, is the camera type used on smart motorways. They are small, often grey rather than yellow, and mounted on overhead gantries, which makes them easy to miss.
Crucially, they enforce variable speed limits. When a smart motorway displays a reduced limit in a red circle, that limit is legally binding and the HADECS camera enforces it. If no limit is shown, the national limit applies. They can monitor multiple lanes at once.
Smart motorways enforce variable limits, and the full motorway driving rules explain how they work.
What are the new AI speed cameras?
Newer cameras use artificial intelligence to analyse images automatically. Rather than only measuring speed, they photograph the inside of the vehicle and use software to flag possible offences for a human officer to review.
These cameras have been trialled and rolled out at various sites across England and Wales. They are part of a wider shift from cameras that do one job to cameras that screen for several offences at once from a single image.
Newer cameras can spot phone use too, so know what the mobile phone law actually says.
What can AI speed cameras detect beyond speed?
This is what sets them apart. As well as speed, AI cameras can flag drivers apparently using a handheld mobile phone and occupants who appear not to be wearing a seatbelt. The software identifies likely offences, and a trained officer then reviews the image before any penalty is issued.
So a camera you assume is only watching your speed may also be checking whether you are holding a phone or belted in. The penalties for those offences are separate and, in the case of a phone, more severe than most speeding tickets.
What happens when a speed camera catches you?
If a camera catches you, the registered keeper of the vehicle is sent a Notice of Intended Prosecution (NIP) and a request for driver details, normally within 14 days. You must return the details confirming who was driving, even if that was not you, within the time stated.
From there you may be offered a fixed penalty, usually £100 and 3 points, a speed awareness course if eligible, or a court summons for higher speeds. Ignoring the notice is itself an offence that carries 6 points.
Caught on camera? Our guide to speeding fines explains the bands and your options.
Most points come from cameras, and how the penalty points system works explains totting up.
Speed and stopping distance are directly linked, and our guide to UK stopping distances explains how much extra room you need at higher speeds.
Do speed cameras work in both directions?
Some do and some do not. A single rear-facing Gatso photographs traffic travelling away from it in the lanes it covers, while other fixed cameras are positioned to catch one direction only. Average-speed camera networks are usually set up to monitor both directions of travel.
The safe assumption is that any camera could be active and could be catching your direction, rather than trying to judge which way a given camera faces at speed. Mobile camera operators can also set up on either side of a road. Treating the limit as the limit, everywhere, is far simpler and more reliable than trying to work out where and which way each camera is pointing.
How a speeding conviction affects your insurance
A speeding endorsement almost always raises your premium, and you must declare it when you get a quote, typically for five years. The size of the increase depends on the offence code and the rest of your profile.
The full picture, including how long you must declare it and which codes cost most, is covered in our guide on how penalty points affect car insurance.
Frequently asked questions
How do average speed cameras work, and are they always on?
They photograph your number plate at two points and calculate your average speed over the distance between them. They run continuously, so slowing only at each camera does not help. If your average across the stretch is over the limit, you are caught.
Do all speed cameras flash when they catch you?
No. Many modern cameras use infrared rather than a visible flash, so you may not notice anything at all. Never rely on seeing a flash as confirmation of whether you were caught. Some cameras are also rear-facing, with any flash appearing behind you.
What is a HADECS camera and where are they used?
HADECS is the camera system used on smart motorways. The cameras are small and mounted on overhead gantries, and they enforce the variable speed limits shown on the signs. When a reduced limit is displayed in a red circle, it is legally binding.
What can the new AI cameras detect beyond speeding?
AI cameras can flag apparent handheld mobile phone use and occupants who do not appear to be wearing a seatbelt, as well as speed. The software highlights likely offences, and a human officer reviews the image before any penalty is issued.
What is a Notice of Intended Prosecution and how long do you have to respond?
It is the notice sent to the registered keeper after a camera offence, usually within 14 days. It asks you to confirm who was driving, and you must respond within the time stated, normally 28 days. Failing to respond carries 6 points itself.
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