UK speed limits: the law explained

Last updated July 19th, 2023

Speed limits are nothing new. In fact, the very first UK speed limit was introduced all the way back in 1861, when vehicles were limited to just 10mph as part of the Locomotives on Highways Act.

Of course, since then, transport has become faster and more sophisticated – and speed legislation has been adjusted accordingly. Most notably, different speed limits have been introduced for various areas, road types and vehicles.

This has led to some confusion among drivers, who may encounter situations where they are unsure what speed limit applies.

In this guide, we will explain the national speed limits that apply for different vehicle and road types. Then, we’ll cover how and why local speed limits are set by local authorities.

We’ll also clarify some frequently misunderstood aspects of speed limit legislation, including fixed, variable and minimum speed limits – and the penalties that may apply if you are caught breaking a speed limit.

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National speed limits by road and vehicle

Built-up areas mph (km/h) Single carriageways mph (km/h) Dual carriageways mph (km/h) Motorways mph (km/h)
Cars, motorcycles, car-derived vans and dual-purpose vehicles 30 (48) 60 (96) 70 (112) 70 (112)
Cars, motorcycles, car-derived vans and dual-purpose vehicles when towing caravans or trailers 30 (48) 50 (80) 60 (96) 60 (96)
Motorhomes or motor caravans (not more than 3.05 tonnes maximum unladen weight) 30 (48) 60 (96) 70 (112) 70 (112)
Motorhomes or motor caravans (more than 3.05 tonnes maximum unladen weight) 30 (48) 50 (80) 60 (96) 70 (112)
Buses, coaches and minibuses (not more than 12 metres overall length) 30 (48) 50 (80) 60 (96) 70 (112)
Buses, coaches and minibuses (more than 12 metres overall length) 30 (48) 50 (80) 60 (96) 60 (96)
Goods vehicles (not more than 7.5 tonnes maximum laden weight) 30 (48) 50 (80) 60 (96) 70 (112)
60 (96) if articulated or towing a trailer
Goods vehicles (more than 7.5 tonnes maximum laden weight) in England and Wales 30 (48) 50 (80) 60 (96) 60 (96)
Goods vehicles (more than 7.5 tonnes maximum laden weight) in Scotland 30 (48) 40 (64) 50 (80) 60 (96)

Note: A car-derived van is a small goods vehicle with a design that has been based on the pre-existing design of a passenger car.

Source: UK Government speed limits

National speed limits explained

The national speed limit on motorways and dual carriageways is generally 70mph for cars – and the national speed limit on single carriageways is slightly slower at 60mph. You’ll know when the national speed limit applies, as you’ll see a round white sign with a thick black diagonal stripe across it.

Please note: You must keep to different motorway speed limits when towing a caravan or trailer.

A sign featuring the number ‘30’, bordered by a red circle represents the national speed limit of 30mph for built-up roads, such as those found in suburban areas.

The police enforce these speed limits using average speed cameras or by placing vans equipped with speed cameras in areas where speeding is common. Being caught speeding can carry a range of penalties, from speeding fines and driving licence penalty points, through to mandatory speed awareness courses – and even driving bans for repeat offenders.

National Speed Limit Sign

Local speed limits explained

Local authorities have the power to introduce local speed limits on roads that are deemed dangerous or accident hotspots.

These limits must be clearly signposted and are often enforced in residential areas, near schools or in areas with lots of pedestrians and cyclists. 20mph speed limits are not uncommon in these areas.

Local speed limits are often enforced with chicanes or speed humps (which help to physically slow traffic) rather than with deterrents such as speed cameras.

In some circumstances, local councils will set a 50mph limit on a road that technically qualifies for the 60mph national speed limit but is more susceptible to accidents due to the presence of sharp bends or uneven surfaces.

Local speed limit sign

Fixed speed limits explained

The most common type of speed limit is a ‘fixed speed limit’ (indicated by a circular road sign with a red outline - and the speed limit itself displayed in the centre).

These speed limits are commonly set between 20 and 50mph - and are generally enforced within urban areas which do not require traffic calming measures (or lower local speed limits).

The signs indicating the start of a fixed speed limit zone are generally placed at the beginning of a stretch of road. Drivers should obey these limits until they see a different sign indicating that they no longer apply.

As with national speed limits, being caught breaking a fixed speed limit can result in a fine, penalty points – or even a driving ban. Different types of speed cameras and police vans are used to catch out drivers who don’t comply.

Fixed speed limit sign (30 mph)

Variable speed limits explained

Variable speed limits were introduced relatively recently. They have been implemented on various smart motorways across the UK.

As the name suggests, variable speed limits change throughout the day depending on the flow of traffic, adjusting to reduce congestion as needed. Speed limits are typically reduced when traffic is heavy, then increased once congestion eases.

Drivers are kept up to date with changing limits with signs on digital gantries – and live updates on their navigation systems.

With variable speed limits currently in place on the M1, M6, M25 - and many other UK motorways, it appears that this system is going nowhere. So, keep an eye out for variable limits whilst using smart motorways.

Drivers caught breaking variable speed limits face the same penalties as those breaking the national speed limit.

Variable speed limit sign on the motorway

Minimum speed limits explained

Minimum speed limits are introduced in areas where driving too slowly could lead to traffic jams or increase the risk of collisions, such as tunnels.

This is the rarest type of speed limit on UK roads. However, if you do encounter a minimum speed limit zone, this will be indicated by a round blue sign containing the minimum speed drivers must travel.

Once you reach the end of the zone, you’ll encounter another variation of the sign, this time with a red diagonal line through the number.

Contrary to what many drivers might think, there is no official minimum speed limit in place on UK motorways. However, if you are caught by the police driving at a dangerously low speed on a busy road, you could receive anything from a verbal warning to a careless driving charge.

60 mpg minimum speed limit sign

How much can you legally go over the speed limit in the UK?

It is illegal to drive even 1mph over the speed limit at any time. Driving anywhere outside of the legal speed limit could potentially lead to prosecution.

You may escape with a verbal warning if your speed is no more than 10% (+ 2mph) over the limit in question. However, we strongly recommend that you always drive within speed limits to avoid falling afoul of the law.

You can work out how much you may be fined with our free speeding fine calculator.

If you ever feel that you have wrongfully received a speeding fine, please visit our guide to appealing a speeding ticket.

There are no road signs – how do I know the speed limit?

The beginning of a new speed limit zone will always be indicated by a road sign. In some cases, the limit will also be painted onto the road.

However, even if you do miss the signs, you can often pick up on clues in the area itself to help you figure out how fast you should be travelling:

  • If there is a school or busy cluster of shops nearby, you may be in a 20mph zone.
  • Residential areas are usually covered by a 30mph limit.
  • 40mph roads usually have minimal pedestrian activity, few houses (or none at all) and are generally part of the route in and out of a town rather than within it.

What is a speed limiter?

A speed limiter is a safety device that restricts a driver’s ability to exceed a pre-determined speed limit. There are two kinds of speed limiters available – adjustable speed limiters and intelligent speed limiters.

An adjustable speed limiter allows the driver to set the maximum speed that they want to be able to drive at. Once set, the car will be unable to exceed this limit. As the name indicates, this type of limiter can be adjusted according to the driver’s needs.

An intelligent speed limiter is linked to a camera with the ability to identify and register speed limit signs. If the camera spots a speed limit sign, the limiter will adjust itself so that the car cannot exceed this limit.

Intelligent speed limiters aren’t foolproof; the camera might miss some road signs or misread numbers signposted elsewhere as speed limit signs. Therefore, drivers with intelligent speed limiters are still advised to keep an eye on their speed at all times.

When are speed limiters a legal requirement?

As of July 2022, all new cars sold in Europe must be fitted with a technology called ‘Intelligent Speed Assist’ (a built-in intelligent speed limiter). This also affects UK drivers due to the high volume of European vehicles sold overseas.

Frequently Asked Questions

The national speed limit is 70mph on both motorways and dual carriageways. 60mph is the speed limit on single carriageways.

There is no official legal minimum speed limit on the motorway. However, if you are caught driving at a low speed on the motorway, you may be pulled over by police.

You could be prosecuted if your driving is deemed ‘dangerous’. This is due to the increased risk of serious accidents associated with driving slowly in high-speed areas.

70mph is the highest speed limit in the UK, applying to cars, motorbikes, dual-purpose vehicles and car-derived vans on dual carriageways and motorways.

Even in areas with no minimum speed limit, you may be prosecuted for driving too slowly, if your driving is deemed dangerous. (Driving very slowly can increase the risk of accidents on busy or high-speed roads.)

It is illegal to drive above the speed limit under any circumstances, even in the event of an emergency. Only registered emergency vehicles (i.e. ambulances, police cars and fire engines) are permitted to exceed speed limits.

The start of a new speed limit zone is always indicated by a road sign, with the speed limit also painted onto the roads in some circumstances.

If a road has streetlights every 200 yards or less - and there are no signs stating otherwise, this usually indicates that it is a 30mph zone. Streetlights are generally only used on roads where pedestrians are present, such as residential areas.