 If they passed their car driving test on or after 1 January 1997, they may drive a car or van up to 3,500 kg maximum authorised mass (MAM) towing a trailer of up to 750 kg MAM, and they may tow a trailer over 750 kg MAM as long as the combined MAM of the trailer and towing vehicle is no more than 3,500 kg MAM when loaded.They must pass the car and trailer driving test to tow anything heavier.If a driver passed their car test before 1 January 1997, they are usually allowed to drive a vehicle and trailer combination up to 8,250 kg MAM.