The test is regarded by the DVSA as the first step to pulling large trailers. The duration of the test is approx 90 mins.

The 85% rule is a safety guideline recommending that a fully laden caravan or trailer should not exceed 85% of the tow car's kerbweight, aiming to ensure stability, particularly for novice drivers.

It is not legally binding but is widely advised by towing experts and clubs.

For experienced drivers, this limit can be increased up to 100%.

If you passed your car test on or after 1 January 1997, you are limited to smaller combinations, and you will still need to pass an additional driving test (B+E) to tow heavier trailers/caravans.

Key Rules and Requirements

• Weight Restrictions: The trailer's MAM (maximum weight when loaded) must not exceed 3,500kg.
• Vehicle Capacity: You must not exceed your car’s towing capacity listed in the handbook or on the VIN plate.
• Licence Categories: Your licence must show you have category B (car) and BE (car + trailer) entitlement. If B+E is not on your licence, it will be added by the DVLA the next time you renew it.
• Safety Requirements: The trailer must have two red stop lamps, an illuminated number plate, two triangular red reflectors, and working amber indicators.

Towing Capacity Example
Even if your licence allows a 3,500kg trailer, your car must be capable of towing it. For instance, a 2.5-ton 4x4 can tow a 3.5-ton caravan, provided the total combination weight does not exceed the vehicle's safe capacity.

Always check your specific licence entitlements via NIDIRECT's view your driving licence service to confirm what you are allowed to drive.

Your entitlement to tow a caravan or trailer will depend on the driving licence you hold. The categories detailed on your driving licence will decide what you can tow.  Full details can be found on the NI Direct website.

Got first car licence on or after 19/1/2013

Drivers who pass a test for Category B+E (Car and Trailer combination) on or after the above date, will be restricted to towing a trailer not heavier than 3,500kg and the shared MAM of the car and trailer must not be more than 7,000kg.

To tow a trailer that weighs more than 3,500kg with a car/ small vehicle (category B), you will need to pass additional tests for category C1+E (medium-sized goods vehicles with trailers).

Got first car licence on/ after 1/1/1997 but before 19/1/2013

Drivers who passed a car test on or after 1 January 1997 but before 19 January 2013 need to pass a further driving test to gain entitlement to category B+E (Car and Trailer combinations) and also for all larger vehicles.

As well as the new driving tests, drivers of vehicles which fall within subcategories C1, C1+E, D1 and D1+E also have to meet higher medical standards.

Category B entitlement holders may still tow a trailer; however certain restrictions apply, see the following link for further details.

Car licences held before 1 January 1997
Drivers who passed a car test before 1 January 1997 (within the UK) may retain their earlier existing entitlement to tow trailers, unless their licence has been restricted.

This means they are generally entitled to drive a vehicle and trailer combination that falls within B+E entitlement and up to 8,250kgs MAM for holders of C1+E. They also have entitlement to drive a minibus with a trailer over 750kgs MAM.

Drivers who hold subcategory C1+E - limited to 8,250kgs MAM - may apply for provisional entitlement to the new subcategory C1+E to take and pass the test which will increase their shared vehicle and trailer entitlement to 12 tonnes MAM.

It is not necessary to gain subcategory C1 entitlement first, but drivers have to meet higher medical standards and pass both the category C theory test and the subcategory C1+E practical test.

In the UK, the maximum legal gross weight for an unbraked trailer is 750 kg. However, the trailer must not exceed half the towing vehicle's kerb weight.

Regardless of this, you must always adhere to the maximum towing capacity specified by the vehicle manufacturer, found in the handbook or on the VIN plate.

Key points regarding unbraked trailer weights in the UK:

• The 750kg Rule: You cannot legally tow an unbraked trailer that has a Maximum Authorised Mass (MAM) exceeding 750kg.
• Kerb Weight Restriction: If the car's 50% kerb weight is lower than 750kg, that lower figure becomes your legal maximum.
• Safety Plate: All trailers must be clearly marked with their maximum gross weight in kg.
• Insurance & Safety: Ensure your vehicle's fully loaded weight does not exceed the maximum towable mass.

  Always check your specific vehicle's identification number (VIN) plate—normally located under the bonnet or inside the driver's door—to find the exact gross train weight for your car.

Avoid:

• Exceeding vehicle towing limits:  Always check your handbook or manufacturer spec.
• Using the wrong number plate: Your trailer must display the same registration as your tow vehicle.
• Incorrect or missing breakaway cables: A legal requirement for braked trailers.
• Poorly secured loads: Straps should be rated and checked before travel.
• Travelling with unbalanced loads: Which increases sway and braking risk.

When in doubt, ask a trailer specialist to assess your setup before you hit the road.