A simple trailer is the commonest variety and has a single axle. Even a simple trailer can put a large weight on the rear of a tow vehicle and potentially interfere with steering, braking and traction by unweighting the front axle.
Make sure the trailer coupling and the tow ball are an appropriate fit. Modern tow balls are 50mm in diameter, slightly larger than older ones (47.6mm). All trailers require a safety chain in case the coupling device breaks. The chain must be short enough that it prevents the trailer coupling from dragging on the ground.
Your trailer requires a Warrant of Fitness (WoF) and registration.
If the trailer hasn't been used for a long time, check tyre pressures, tread depth, wheel bearings and whether the warrant is still current.
It must have amber or white forward-facing side lights if its width exceeds two metres and if it was registered after 1977. If it is wider than 1.5 metres it requires two tail-lights. If first registered after 1977, it must also have two stop lights. However the latter are not needed if arm signals or tow vehicle stop-lights can be seen by following drivers.
Similar rules apply for indicators. Two red reflectors are also required by law and a white light to show the trailers registration.
When packing the trailer, ensure the load is evenly distributed. If it is unbalanced, it may cause swaying.
Ensure your load is properly secured. No part of the load should be in contact with the ground, and nor should any part of the load extend more that 1.25m either side of the centre line of the trailer.
If the load extends, more than 1.0 metre behind the trailer, attach a white, red, orange or yellow fluorescent flag to indicate where the load ends. The load must not extend more than 4.0m behind the axle or the mid-point of the tow trailer axles
Check there is a downwards force - around 30-40kg - on the towball because any less and trailer stability may be affected. The drawbar should appear level or slightly nose down
Avoid filling your hatch or boot with gear as this will further unload the front axle.