Hiring a large plant trailer involves more than choosing the right ramp angle or deck length. Before the trailer leaves the yard, the hirer must confirm that their driving licence covers the load, that their towing vehicle can handle the weight, and that the trailer itself is fit for the road. Getting any of these three things wrong can mean a DVSA prohibition, invalidated insurance, or a dangerous journey. This guide sets out what to check, in the order you should check it.
Driving Licence: What Your Category Allows You to Tow
The starting point is the driving licence. You can tow trailers up to a certain weight with your car driving licence, and the weight you are allowed to tow depends on when you got your licence. You will need to know the weight of both the vehicle and trailer, also known as the maximum authorised mass (MAM). The MAM is listed in the owner's manual and is normally shown on a plate or sticker fitted to the vehicle or trailer.
If you passed your car driving test from 1 January 1997, you are now allowed to tow trailers up to 3,500kg MAM. Drivers who got their licence before 1 January 1997 are usually allowed to drive a vehicle and trailer combination up to 8,250kg MAM. Large plant trailers carrying a mini-digger or a tracked dumper can easily push into and beyond the 3,500kg band, so check the trailer's plate before you assume your standard licence is sufficient.
If the trailer's MAM exceeds 3,500kg and your licence was issued from 1 January 1997, you will need an additional category. Drivers who got their licence from 1 January 1997 and need to tow a trailer with a MAM over 3,500kg will need to apply for a provisional licence for a medium-sized lorry and trailer (category C1+E) and pass the relevant tests. You can check your current entitlements on GOV.UK's view-driving-licence service before you book.
Vehicle and Trailer Weight: The Three Figures That Must All Fit
Licence category is only one constraint. The towing vehicle itself imposes two more: its rated towing capacity and its gross train weight (GTW).
Check your car's handbook to find out its gross train weight. This is the total allowable weight of the car plus the trailer plus the load. Three things decide your limit: your licence category, your vehicle's towing rating from the manufacturer, and the trailer's own MAM. Whichever of those three is lowest is your limit, with no exceptions.
The 3,500kg limit applies to the trailer MAM, but the combined gross train weight of your vehicle and trailer must also stay within your licence entitlement. A large 4x4 or a pickup truck will have a higher towing rating than a standard car, but it still has a ceiling. Always add the figures together before you collect.
For large plant trailer hire, the payload matters just as much as the trailer's unladen weight. Confirm the plant's weight with your hire company and do the arithmetic before you set off.
Brakes, Breakaway Cable and Coupling
Large plant trailers will always require brakes. Your trailer must have a working brake system if it weighs over 750kg when it is loaded.
Braked trailers should also have a correctly fitted breakaway cable that applies the trailer brakes if the trailer becomes detached.
Before accepting the trailer from the hire company, ask to see the overrun braking mechanism operate and check that the breakaway cable is present, intact and correctly attached to the towing vehicle's chassis point, not just looped around the towball.
Lights, Number Plate and Pre-Journey Checks
These must be clearly visible, securely mounted, and not obscured by loads or accessories.
The trailer must display the same registration as the towing vehicle. It must be clearly visible and meet UK number plate rules.
A fully functioning lamp can still fail the practical legal test if a load, ramp, mudguard or other fitting hides it. Rear lights and reflectors need to remain visible, and the number plate must not be obscured. If a load overhangs the trailer, it may need its own marker board or lighting arrangement.
Pre-collection checklist
- Confirm the trailer's MAM from its plate and compare it with your licence category and your vehicle's towing rating and GTW.
- Calculate the laden weight: trailer unladen weight plus the weight of the plant you are carrying.
- Check the overrun brake mechanism engages and releases smoothly.
- Check the breakaway cable is present and fitted correctly.
- Test all lights with the trailer connected: sidelights, brake lights, both indicators, fog light, and number plate lamp.
- Confirm the number plate matches your towing vehicle and is unobscured.
- Check tyre condition and pressures on all trailer axles.
- Confirm ramp pins or beavertail locking catches are secure after loading.
- Check that lashing points and tie-down straps or chains are rated for the load and correctly tensioned.
Speed Limits When Towing a Large Plant Trailer
Many drivers are unaware that hitching a trailer changes the speed limits that apply to them. These reduced limits apply regardless of the national speed limit posted for other traffic on the same road. You can be fined up to £2,500, be banned from driving and get 3 penalty points for using a vehicle in a dangerous condition. Exceeding a speed limit while towing adds road traffic offences on top of any mechanical risk.
What to Confirm with the Hire Company Before You Book
A reputable hire company should be able to answer every question below before you commit. If answers are vague, treat that as a reason to keep looking. Browse trailer hire listings and compare local options before booking.
- Trailer MAM and unladen weight - ask for both figures, not just one.
- Payload capacity - confirm it covers the plant you intend to transport.
- Braking system type - overrun brakes are standard on most plant trailers; confirm the system is in working order and when it was last inspected.
- Breakaway cable - confirm it is present and rated correctly.
- Lighting - ask whether the lighting board or wiring loom was checked before the trailer was made available.
- Towball size and coupling head - the coupling head on the trailer must match the towball on your vehicle; the standard UK size is 50mm but confirm this.
- Ramp or beavertail condition - ask about ramp angle and ground clearance for the plant you are loading.
- Insurance and damage liability - clarify what is covered under the hire agreement and what excess applies.
If you are based in or travelling through a particular area, local hire depots can save significant transport time. GetBrent lists trailer hire in London, trailer hire in Maidstone and trailer hire in Daventry among many other locations, making it straightforward to find a nearby supplier and compare what is available.
GetBrent is a UK marketplace connecting hirers with local trailer hire companies, plant hire firms and trades. Search the listings to find a vetted supplier near you, check availability, and confirm the specification of the trailer before you travel to collect it.
