Taken from - https://www.gov.uk/towing-with-car/d...at-you-can-tow
Driving licence rules and what you can tow
The rules on what you can tow are different depending on when you passed your driving test.
The rules are changing for new licences issued from 19 January 2013 onwards.
Licences held from 1 January 1997
If you passed your driving test after 1 January 1997 and have an ordinary category B (car) licence, you can drive either:
a vehicle up to 3.5 tonnes or 3,500 kilograms (kg) Maximum Authorised Mass (MAM) towing a trailer of up to 750kg MAM (with a combined weight of up to 4,250kg in total)
a trailer over 750kg MAM as long as it is no more than the unladen or ‘kerb’ weight of the towing vehicle (with a combined weight of up to 3,500kg in total)
For anything heavier you need to take a category B+E driving test.
Licences held before 1 January 1997
If you passed your car test before 1 January 1997 you are generally entitled to drive a vehicle and trailer combination up to 8.25 tonnes MAM.
This is the weight of a vehicle or trailer including the maximum load that can be carried safely when it’s being used on the road.
You also have entitlement to drive a minibus with a trailer over 750kg MAM.
Licences issued from 19 January 2013
From 19 January 2013, drivers passing a category B (car and small vehicle) test can tow:
small trailers weighing no more than 750kg
trailers weighing more than 750kg, where the combined weight of the towing vehicle and the trailer isn’t more than 3,500kg
If you want to tow a trailer weighing more than 750kg, when the combined weight of the towing vehicle and trailer is more than 3,500kg, you’ll have to pass a further test and get B+E entitlement on your licence.
You’ll then be able to tow trailers up to 3,500kg.
Towing heavier combinations
If you want to tow heavier combinations, you’ll have to first apply for provisional entitlement to the new C1+E entitlement. You’ll then have to pass the category C theory test and C1+E practical test.
Once you’ve done this you can drive vehicles and trailers with a combined weight of up to 12 tonnes MAM.