• An approved style number plate must be fitted.
• This must comprise black letters on a reflective yellow background, the same as the rear plate on a motor vehicle.
• It must carry the registration number of the towing vehicle and must be illuminated at night.

Note: Make sure that any towbar fitted does not obscure your number plate on the tow vehicle, Number plates should be seen and easily read.

A properly fitted, good quality towbar with the correct specification for the vehicle is essential. Anything less can compromise safety.
Towbars fitted to new category M1 vehicles (passenger carrying vehicles with up to eight seats plus the driver) with EC Whole Vehicle Type Approval manufactured after 1st January 1996 and first registered after 1st January 1998 must be approved under Directive 94/20/EC - Mechanical Coupling Devices for fitting to the vehicle model concerned.
However, it should be noted that this does not apply to commercial vehicles, and that non-EC approved towbars fitted to any vehicles prior to 1 January 1998 will not be required to be removed.
If in any doubt consult the vehicle manufacturer / dealer or a reputable towbar manufacturer.
The Directive requires that the towbar is tested for two million cycles at a loading of 20 per cent higher than for the current BSI and ISO specifications, and that it attaches to all of the fixing points specified by the vehicle manufacturer. Any part of the towbar or towball that obscures the vehicle registration plate must be detachable when not in use.
The Directive also requires that approved towbars are marked with the "S" value (the maximum vertical static load in Kg) and the "D" value (a figure calculated from the maximum gross weight of the trailer and the maximum gross weight of the towing vehicle and expressed in kN).
It is essential that the maximum "S" value, gross vehicle and trailer weights recommended by the vehicle manufacturers are not exceeded, and vehicle manufacturers are required (under Directive 95148/EC Masses and Dimensions (category M1)) to include this information together with the towbar mounting data in the vehicle handbook.
Where a towbar manufacturer voluntarily marks a figure on the towbar for gross vehicle or trailer weight, this will almost certainly relate to the maximum for the range. Individual models within the range may have lower limits.
The current MoT test for cars does not include checks on the condition of the towbar, its electrical connections or its mounting points.
However, if any of these items are in a poor condition you could be prosecuted for driving a vehicle / trailer combination in an "unroadworthy condition".