Towing a trailer with an HGV involves a specific set of legal requirements, licence entitlements, and practical skills that go beyond those needed for driving a rigid vehicle. Whether you are coupling a semi-trailer to an articulated tractor unit, towing a drawbar trailer behind a rigid lorry, or operating a road train, understanding the rules is essential for legal compliance and road safety. This comprehensive guide explains the HGV towing rules that apply in the UK in 2026, covering licence categories, coupling procedures, weight limits, and the specific regulations that apply to different trailer types.
HGV Licence Categories and Trailer Entitlements
The licence category you hold determines what combinations of vehicle and trailer you are legally permitted to drive. The relevant categories for HGV drivers are:
| Category | Vehicle Type | Trailer Entitlement |
|---|---|---|
| C1 | Rigid vehicle 3,501–7,500 kg GVW | Trailer up to 750 kg MAM (C1 licence); trailer over 750 kg MAM requires C1+E |
| C1+E | Rigid vehicle 3,501–7,500 kg GVW | Trailer over 750 kg MAM; combined weight up to 12,000 kg |
| C | Rigid vehicle over 3,500 kg GVW | Trailer up to 750 kg MAM (C licence); trailer over 750 kg MAM requires C+E |
| C+E | Articulated or drawbar combination | Any trailer; combined weight over 3,500 kg |
The C+E category covers both articulated lorries (tractor unit + semi-trailer) and drawbar combinations (rigid lorry + full trailer). If you hold a C+E licence, you are entitled to drive both types of combination. If you only hold a C licence, you may tow a trailer with a maximum authorised mass (MAM) of up to 750 kg — for example, a small plant trailer or a car transporter trailer — but you must not tow a trailer over 750 kg MAM without upgrading to C+E.
Maximum Weight Limits for HGV Combinations
The maximum permitted weights for HGV combinations in the UK are set by the Road Vehicles (Authorised Weight) Regulations 1998:
| Combination Type | Maximum Train Weight | Conditions |
|---|---|---|
| 2-axle rigid + 1-axle trailer | 25,000 kg | Standard road |
| 2-axle rigid + 2-axle trailer | 32,000 kg | Standard road |
| 3-axle articulated (2+1 or 1+2) | 38,000 kg | Standard road |
| 4-axle articulated (2+2) | 38,000 kg | Standard road |
| 5-axle articulated (3+2 or 2+3) | 40,000 kg | Standard road |
| 6-axle articulated (3+3) | 44,000 kg | Standard road |
| Road train (drawbar) | 44,000 kg | 6 axles minimum |
Individual axle weight limits also apply — no single axle may carry more than 10,000 kg (non-drive axle), 11,500 kg (drive axle), or 8,000 kg (steering axle). Exceeding axle weight limits is an offence even if the total train weight is within the permitted maximum. See our guide on HGV overloading fines for the penalties that apply.
Coupling a Semi-Trailer: The Fifth Wheel Procedure
Coupling a semi-trailer to a tractor unit using a fifth wheel coupling is one of the most safety-critical procedures an HGV driver performs. An incorrectly coupled trailer can detach at speed, with potentially fatal consequences. The correct procedure is:
- Position the tractor unit: Reverse slowly towards the trailer, aligning the fifth wheel with the trailer's kingpin. The fifth wheel should be at the correct height — slightly lower than the trailer's front underrun, so the trailer slides up onto the fifth wheel as you reverse under it.
- Reverse under the trailer: Reverse slowly until you feel and hear the kingpin engage in the fifth wheel jaw. Do not reverse too fast — this can damage the kingpin or fifth wheel.
- Check the coupling: Apply the tractor unit parking brake. Get out and visually inspect the fifth wheel from both sides. The kingpin should be fully engaged in the jaw, and the locking device should be in the locked position. Attempt to pull forward gently — the trailer should not move.
- Connect the air lines: Connect the red (emergency) and yellow (service) air lines to the trailer. Check that the connections are secure and not leaking.
- Connect the electrical cable: Connect the electrical cable (7-pin or 15-pin) to the trailer. Check that all trailer lights are working.
- Raise the landing legs: Wind up the trailer landing legs fully and secure the winding handle.
- Check trailer brakes: Check the trailer brake warning light on the dashboard. Apply and release the trailer brake to confirm it is functioning.
- Final check: Walk around the complete combination and check all lights, tyres, and connections before setting off.
Uncoupling a Semi-Trailer
Uncoupling must also be done correctly to prevent the trailer from falling or rolling away. The procedure is:
- Park on a firm, level surface. If the surface is not level, chock the trailer wheels before uncoupling.
- Apply the trailer parking brake.
- Lower the landing legs until they are firmly on the ground and supporting the trailer weight.
- Disconnect the electrical cable and air lines.
- Release the fifth wheel locking device.
- Drive the tractor unit forward slowly until the kingpin clears the fifth wheel jaw. Do not drive forward too fast.
- Check that the trailer is stable and the landing legs are secure before leaving the vehicle.
Drawbar Trailers
A drawbar trailer is a full trailer (with its own front axle and steering) towed by a rigid lorry using a drawbar coupling. Drawbar combinations are common in distribution and retail logistics. The coupling procedure for a drawbar trailer differs from a fifth wheel:
- The drawbar eye must be connected to the towing vehicle's drawbar coupling and the coupling pin secured
- The safety chain or breakaway cable must be connected — this applies the trailer brakes automatically if the trailer becomes detached
- The air lines and electrical connections must be made as for a semi-trailer
- The trailer's front axle steering must be checked — the trailer should track correctly behind the towing vehicle when turning
Speed Limits for HGV Combinations
HGV combinations are subject to the same speed limits as rigid HGVs over 7.5 tonnes:
| Road Type | Speed Limit (HGV over 7.5t) | Speed Limit (Car) |
|---|---|---|
| Motorway | 60 mph | 70 mph |
| Dual carriageway | 50 mph | 70 mph |
| Single carriageway | 40 mph | 60 mph |
| Built-up area (30 mph zone) | 30 mph | 30 mph |
These limits apply to the combination as a whole. There is no separate speed limit for the trailer. See our guide on HGV speed limits for more detail on the rules that apply in different situations.
Trailer Maintenance and Roadworthiness
The driver is responsible for checking the trailer as part of the daily walkaround check. The trailer must have a valid annual test (equivalent to an MOT for trailers), and the operator must maintain a record of all trailer inspections and repairs. Trailers must be fitted with reflective rear markings, an underrun bar, side guards (on trailers over 3.5 tonnes), and ABS brakes (on trailers first used after 1 October 1997). See our guide on HGV load securing rules for the requirements that apply to loads carried on trailers.
Abnormal Loads and Special Types
Some trailer combinations — such as low-loaders, extendable trailers, and multi-axle trailers — are classified as abnormal loads and are subject to additional regulations. See our guide on HGV abnormal load rules for the specific requirements that apply to these vehicles.
Start Your HGV Training with GS Driver Training
GS Driver Training has helped thousands of drivers qualify since 1996. We offer Class 1 (C+E), Class 2 (C), C1, ADR, and CPC training from our facility in Surrey. Our Class 1 (C+E) training covers all aspects of coupling, uncoupling, and driving articulated combinations. View our courses or call 01252 447808.
