UK speed camera tolerances revealed

Some speed cameras have tolerances. This is to account for variations in speed camera models as well as the differences between different car’s speedometers. 

This means that some speed cameras might not trigger if you’re a few miles over the speed limit. But this is never an excuse for breaking the speed limit. 

It’s also worth bearing in mind that not all speed cameras flash. Some use infra-red technology to calculate a vehicle's average speed. So if you don’t see a flash, it doesn’t automatically mean you won’t get a speeding ticket. Here’s what you need to know.

UK fixed and mobile speed camera tolerances

Speed camera tolerances exist to improve driver safety. One of the reasons is so drivers have their eyes on the road instead of their speedometer. They also exist because there are variations in speedometers and the speed cameras themselves.

But tolerances aren't an excuse for breaking the speed limit. The Metropolitan police said that no matter what the threshold, drivers should always stick to the speed limit and never exceed it.

What our motor insurance expert says

"Speed camera tolerances are discretionary. That means police can still prosecute you even if you go just 1 mph over the speed limit. And a speeding conviction comes with a fine, points on your licence and higher future car insurance costs. It's not worth it- you should always drive at a speed that's legal, safe and appropriate for the road."

Louise Thomas Motor insurance expert

We contacted 45 UK police forces*. Of the 39 that responded, 26 shared information about when their speed cameras activate if a driver is going above the speed limit.

Most police forces have a tolerance of 10% plus 2mph above the limit before a speed camera ‘flashes’.

Here’s how some of the forces responded:

*We issued a Freedom of Information request in February 2023 asking "Is there a speed tolerance on the fixed cameras used in your force area, and if so, what is the tolerance? For example, 10% + 2mph."

Do average speed camera tolerances work in the same way?

Average speed cameras are different to normal fixed and mobile speed cameras. Average speed cameras check your speed over several miles, rather than measuring your speed over a short distance.

This means they should be more accurate and so might not have the same tolerance levels as other speed cameras.

What's the range of a mobile speed camera van?

The typical range of a mobile speed camera van is around 1-2 miles on a straight stretch of road. As you might expect, they can't see through or around bends. The speed detecting technology used also impacts the overall range of the mobile speed camera.

Speed camera tolerances and their enforcement

Speed camera tolerances are used at the discretion of the police to follow the rules around speeding, speed cameras, and the law.

Technically, the Association of Chief Police Officers (ACPO) allow a tolerance of 10% + 2 mph on speeding before taking punitive action. So they’re within their rights to punish drivers that break the speed limit by even just a few miles per hour.

You can’t rely on these discretionary thresholds as a defence if you’re flagged for speeding. Going even 1 mile an hour over the speed limit counts as speeding, and you could be punished accordingly if caught.

Depending on the severity of the speeding offence, you might:

• Be offered to take a speed awareness course
• Get a fine
• Have points on your licence
• Be banned from driving

How many cars can a speed camera van catch at once?

Mobile speed cameras can catch speeding vehicles in either direction, coming towards or away from the speed camera van. They can only capture 1 car at any one time, but the technology is fast. They can usually record a car’s speed quickly and move onto another vehicle.

What are the penalties for speeding in the UK?

If the offence is minor, you might be asked to go on a speed awareness course rather than take the fine and points.

For more serious offences, though, that option isn’t available and the minimum penalty for speeding is a £100 fine and 3 penalty points on your licence.

Speeding fines are based on a percentage of your weekly income, with the minimum fine being £100.

This is in addition to getting points on your licence. Our speeding fine calculator lets you work out any potential fine.

I've been flashed by a mobile speed camera van. How long will it be before I get a ticket?

If you've been flashed by a speed camera - whether mobile or fixed, you should get your Notice of Intended Prosecution (NIP) within 14 days of the offence. The NIP is sent to the car's registered keeper. This is taken from DVLA information about the car based on its number plate.

This means you might get a speeding ticket sent to you if one of your named drivers was the one doing the speeding.

Do I need to tell my car insurance company about a speeding ticket?

Yes - you have to declare any unspent speeding convictions or points on your driving licence to your car insurance company.

Although points remain on your licence for 4 years, insurers use them in their calculations for 5 years.

As a result, you could see your car insurance costs go up up because insurers consider you to be a bigger risk.

You don't need to tell them if you've taken a speed awareness course unless they ask you.