UK Trailer Legislation
The following is a summary of the
UK laws applicable to those who wish to tow a trailer.
Weight
For light trailers (less than 3500kg maximum laden
weight), there are no specific laws between the
weight of the towing vehicle and the weight of the
trailer.
For M1 category vehicles (motor vehicles used for
the carriage of passengers and comprising not more
than eight seats, in addition to the driver's seat)
the maximum heavy
haul weight is quoted by the manufacturer. Alternatively,
the manufacturer may provide a maximum gross weight
(the laden weight of the trailer plus the laden
weight of the towing vehicle).
The maximum laden weight of a trailer which may
be towed by a light goods vehicle depends on both
the stated gross train weight of the towing vehicle
(GTW) and the manufacturers recommended maximum
trailer weight. Neither the maximum permissible
trailer weight nor the maximum gross train weight
(the laden weight of the trailer plus the laden
weight of the towing vehicle) should be exceeded.
It is possible that the stated gross train weight
is less than the sum of the stated maximum permissible
laden weight of the towing vehicle and the stated
maximum permissible laden trailer weight. In this
case the towing vehicle and the trailer must be
loaded such that each does not exceed its individual
maximum limit and the sum of both does not exceed
the maximum gross train weight.
It is not a legal requirement to display a notice
of the unladen weight of the trailer or the towing
vehicle, unless the towing vehicle is either a tractor
or a train!
Size
If the towing vehicle has a permissible gross
weight in excess of 3 1/2 tonnes the maximum width
and length of the trailer are 2.55 metres and 12
metres respectively. If however the gross weight
of the towing vehicle is 3.5 tonnes or less then
the maximum permissible width and length are 2.3
metres and 7 metres respectively. In both cases
the overall length of the towing vehicle and trailer
must not exceed either 18m or 18.75m depending on
the towing vehicle.
Braking
Brake requirements essentially require a trailer
with a maximum design laden weight of more 750 kg
to be braked and allow an inertia (overrun) type
braking system to be used up to a maximum permissible
laden weight of 3500kg. In use it is not permitted
to use an unbraked trailer the laden weight of which
exceeds 50% of the kerbside weight of the towing
vehicle. For trailers up to 1500kg laden weight
it is permitted to use a secondary coupling, which
in the event of separation of the main coupling
will retain the trailer attached to the towing vehicle,
prevent the nose of the trailer from touching the
ground and provide some residual steering of the
trailer. Above 1500kg laden weight the trailer must
be fitted with a device to stop the trailer automatically
in the event of separation of the main coupling
and this is normally achieved by a breakaway cable
attached to the parking brake mechanism - the trailer
becomes detached from the towing vehicle.
Other considerations
The above information relates to basic construction
requirements and some aspects of the use of trailers.
In addition it is recommended that you check that
you have the appropriate Driving Licence entitlement
and whether the vehicle or combination of vehicles
requires a tachograph to record driver's hours.
The latter will apply to most vehicles and combinations
of vehicles above 3500kg gross weight for commercial
use.
Warning - make sure your insurance policy
covers towing a vehicle!
