Is the 10% plus 2 mph speed-camera rule law?

Have you heard whispers about a 10% plus 2mph speeding rule? Many drivers assume that they are safe from a speeding conviction if they drive within 10% plus 2mph over the speed limit; This article clarifies the legal position

Is the 10% plus 2 mph speed-camera rule law?

No. There is no legal right to drive at 10% plus 2 mph above the posted speed limit. The offence of speeding is committed if you exceed the applicable limit. Police guidance allows discretion over enforcement, but it does not create a higher legal speed limit or guarantee that no action will be taken below a particular threshold.

What does the law say about exceeding a speed limit?

Section 89 of the Road Traffic Regulation Act 1984 makes it an offence to drive a motor vehicle on a road at a speed exceeding a limit imposed by law.

The section does not add a 10% plus 2mph margin. It does not provide that a 30-mph limit becomes 35 mph for enforcement purposes. Once the vehicle exceeds the lawful limit, the legal ingredients of speeding may be present, subject to the prosecution proving the speed, the applicable restriction and any other issue arising in the case.

The Highway Code also directs drivers to observe the applicable maximum speed limits.

Where does “10% plus 2 mph” come from?

The expression comes from police enforcement and disposal guidance, not from legislation. The 2025 NPCC guidance sets out a nationally consistent approach to enforcement options and recognises that discretion may be exercised beyond the actual limit.

Crucially, the guidance warns against treating the threshold as a “pseudo speed limit”. It states that nothing in the guidance prevents a police force from prosecuting at a speed below the usual guideline threshold, provided the decision is considered on its individual facts.

The practical message is straightforward: an enforcement guideline may influence how a case is dealt with, but it does not give a driver a defence and does not bind every force or operator to ignore a lower excess speed

Do speed-camera accuracy tolerances create a legal buffer?

No. Technical standards governing approved enforcement devices deal with reliability, verification and permissible measurement error. They protect the integrity of the evidence produced by the device.

Those standards do not alter the posted speed limit. You cannot convert a device specification into a personal allowance to exceed the limit. If the accuracy, approval, operation or evidence from a device is genuinely in issue, it must be assessed from the actual prosecution material, and experts are usually required to interpret this data.

When does a speed camera activate?

There is no single guaranteed activation speed for every fixed, mobile or average-speed system. Different devices and local enforcement arrangements may operate in different ways.

Some modern cameras do not produce a visible flash. Average-speed systems calculate speed between points, while mobile devices may be operated by trained personnel. The absence of a flash does not establish that no offence was recorded.

The safe and lawful approach is to treat the displayed limit as the maximum, rather than attempting to calculate an unofficial camera threshold.

What happens after a speed camera records a vehicle?

A Notice of Intended Prosecution and a section 172 requirement will be sent to the registered keeper of the vehicle concerned within 14 days of the vehicle being caught, requiring identification of the driver within 28 days.

The requirement to identify the driver is a separate legal obligation. Ignoring the notice would lead to a prosecution for failing to identify the driver, which can be a significantly more serious offence, with the penalty fixed at 6 points and a fine rather than punishment for the original speeding offence.

Once the driver is identified, the case may be dealt with by a speed awareness course, a fixed penalty or court proceedings. A course is discretionary and is not available simply because you ask for one.

What are the penalties for speeding?

The minimum penalty is a £100 fine and three penalty points. A speed-awareness course may be offered if the police consider it appropriate and you meet the relevant eligibility conditions.

If the case goes to court, the fine is generally linked to your weekly income and the level of speed. The maximum fine is normally £1,000, rising to £2,500 for motorway speeding. The court may impose up to 6 points (depending on the speed alleged) or impose a driving disqualification.

The wider licence position also matters. If you’re at risk of reaching 12 points, you may face a 6-month totting-up disqualification. If you’re a new driver, and your total points reach six within two years of passing your test, your driving licence would be revoked by DVLA, meaning that you would have to retake your theory and practical tests again.

Frequently asked questions:

Can I legally drive at 35 mph in a 30 mph limit?

No. The legal limit remains 30 mph. An enforcement guideline does not turn it into 35 mph.

Must the police allow 10% plus 2 mph?

No. NPCC guidance supports a consistent approach but does not prevent a force from prosecuting below the usual threshold on the facts of an individual case.

What is the usual minimum penalty for speeding?

The usual minimum penalty is a £100 fine and three penalty points. A course may sometimes be offered, while higher speeds or other circumstances may lead to court.

Do I have to respond if I dispute the speed?

Yes. A requirement to identify the driver should not be ignored merely because the alleged speed is disputed. The identification requirement and the speeding allegation are separate issues.

Speak to Ashworth Motoring Law

If you are at risk of losing your driving licence as a result of an offence of speeding or failing to identify the driver, contact Ashworth Motoring Law on 0330 33 22 770 for specialist advice and representation.