Towing a Trailer for Work — UK Licence Rules, Weights and the Law for Trades (2026)

The Licence Rules — and the Big 2021 Change

The single most important thing to understand is what changed at the end of 2021, because a lot of older advice online is now wrong. Since 16 December 2021, anyone who holds a standard car licence (category B) can tow a trailer up to 3,500 kg MAM without taking the separate car-and-trailer test (the old B+E test). The combined limit is the maximum the towing vehicle and trailer are each rated for — there is no longer a category-imposed cap that stops a post-1997 car-licence holder from towing a large plant or tipper trailer.

This replaced a rule that caught out a lot of younger tradespeople. Before the change, anyone who passed their car test on or after 1 January 1997 was generally limited to towing a trailer up to 750 kg MAM — or a larger trailer only where the combined vehicle-and-trailer MAM stayed under 3,500 kg. To tow anything heavier you had to pass the B+E test. That test is no longer required for new entries: passing the car test now automatically grants the right to tow up to the 3,500 kg combined figure.

Drivers who passed their car test before 1 January 1997 generally keep "grandfather rights" — category B+E shows on their licence and they can typically tow heavier combinations (commonly up to 8,250 kg combined). Always check the categories printed on the back of the photocard rather than assuming. If you run a team, check every driver's entitlement before you let them hitch up, and keep a record of it.

MAM and the Four Weight Limits You Must Not Exceed

MAM stands for Maximum Authorised Mass — the most a vehicle or trailer can legally weigh fully loaded, including the load itself. It is sometimes called gross vehicle weight (GVW) or gross trailer weight. The 3,500 kg figure in the licence rule refers to MAM, not to how much you happen to have loaded on the day.

Being licensed to tow is not the same as being legal to tow a given load. You must stay within all four of these at once:

• The towing vehicle's towing capacity — the maximum braked (and separate unbraked) trailer weight the manufacturer permits, found in the handbook or on the VIN plate.
• The trailer's plated weight — its own MAM as stamped on the manufacturer's plate. Load it heavier than this and you're overloaded even if everything else checks out.
• The gross train weight (GTW) — the maximum combined weight of vehicle plus loaded trailer, also shown on the vehicle's plate.
• The axle limits — each axle on the vehicle and trailer has its own maximum. It is possible to be under the overall MAM but still overload a single axle through bad load placement.

The weakest of these four sets your real-world limit. A pickup rated to tow 3,500 kg is no use if your trailer is only plated to 2,000 kg — and the trailer plate wins.

Noseweight and Loading the Trailer Correctly

How you load matters as much as how much you load. Noseweight is the downward force the trailer's coupling exerts on the towball. Too little and the trailer can snake dangerously at speed; too much and you overload the rear of the tow vehicle and lift the front, ruining steering and braking. Both the towball and the vehicle have a maximum noseweight (often 75–100 kg on a car or van) — stay within the lower of the two. A cheap noseweight gauge or even bathroom scales and a length of timber will tell you where you are.

As a rule, place the heaviest part of the load low and over or just ahead of the trailer's axle, then balance lighter items around it. A mini-digger or mower should be positioned so the bulk of its weight sits over the axle, not slung out at the back. Then secure everything with rated ratchet straps or chains to proper lashing points — never bungees. Unsecured loads and overloading are two of the most common trailer offences, and an insecure load is treated seriously because of the danger if it shifts or falls onto the road.

Trailer Safety and Maintenance Checks

Trailers spend most of their life parked outside, often loaded and forgotten, which is exactly why they fail. A short check before every tow is the difference between a legal trip and a roadside prohibition. Work through:

• Lights: all running, brake, indicator and fog lights working and the number plate lit. A trailer board with corroded contacts is one of the most common pull-over reasons.
• Tyres: correct pressure, legal tread, no cracking or perishing. Trailer tyres often fail through age rather than mileage — a tyre with deep sidewall cracks can blow even with plenty of tread, so check the date code and replace old rubber.
• Brakes: trailers over 750 kg MAM must have a working braking system (an overrun coupling on most plant and tipper trailers). Check the brakes engage and release; unbraked trailers (750 kg and under) rely entirely on the tow vehicle.
• Coupling: hitch fully seated and locked onto the ball, the safety catch engaged, and the jockey wheel fully wound up and clamped.
• Breakaway cable: fitted and properly attached to the vehicle (not just looped over the towball) so the trailer brakes apply if it ever separates. On unbraked trailers a secondary safety chain or coupling does the same job.

Beyond the daily walk-round, give trailers a proper periodic safety check — bearings, brake linings, chassis and floor condition — at least annually, and keep a note of it. Most light trailers used in the UK don't need an MOT-style test, but certain heavier commercial trailers over 750 kg fall within testing and registration schemes depending on weight and use, so confirm where your trailer sits if you're running anything substantial. Keeping each trailer's servicing, tyre dates and inspection notes logged against the asset — something Trade2Base can hold alongside your van and fleet records — turns "I think it's fine" into a defensible paper trail.

Speed Limits When Towing

Towing lowers your speed limits, and a lot of drivers don't realise it. When you're towing a trailer in England, Scotland and Wales the national limits are reduced:

• Single carriageways: 50 mph (where the limit would otherwise be 60).
• Dual carriageways and motorways: 60 mph (where the limit would otherwise be 70).
• Built-up areas: the posted limit applies as normal (usually 30 mph).

You also must not use the outside (right-hand) lane of a motorway with three or more lanes while towing, except in restricted circumstances. Lower limits mean longer journeys — factor that into your scheduling rather than rushing and risking a load shifting.

Penalties for Overloading and Unsafe Trailers

Enforcement is real and the DVSA runs roadside checks aimed squarely at vans and trailers. An overloaded or unsafe trailer can lead to:

• Fines — graded by how far over the limit you are; serious overloading can run into hundreds of pounds per offence and can be charged against both vehicle and trailer.
• Penalty points on your licence for offences such as an insecure load or driving a vehicle in a dangerous condition.
• A prohibition notice — the trailer is taken out of service at the roadside until the defect is fixed, which can leave you stranded with a loaded plant trailer you cannot legally move.
• Invalidated insurance — if an incident happens while you were overloaded or towing illegally, your insurer may decline the claim, leaving you personally exposed.

Quick Reference: Towing Entitlement at a Glance

Practical Advice for Staying Legal

Most towing trouble comes down to guesswork, and it's avoidable. Three habits keep you on the right side of the law:

• Know your vehicle's numbers: kerbweight, towing capacity and gross train weight all sit on the VIN plate or in the handbook. Write them down so any driver hitching up knows the limits without hunting for them.
• Weigh the loaded trailer: don't estimate the weight of a mini-digger plus buckets plus a tank of fuel. A public weighbridge costs a few pounds and tells you the truth — do it once for a typical load and you'll know where you stand.
• Do a daily check: lights, tyres, coupling, breakaway cable and load straps, every single tow. It takes two minutes and it's the check the DVSA expects you to have done.

If you run more than one trailer or share them across a team, keep the licence entitlements, plated weights, servicing dates and inspection notes in one place rather than scattered across the cab and your memory. Holding that alongside your vehicle and fleet records in Trade2Base means anyone in the business can confirm a trailer is legal to use before they tow it — and you have the evidence if you're ever stopped.