Trailer Registrations update! August 2025

As of Aug 16th 2025, it is compulsory for. ALL O2 class vehicles (braked trailers between 750kgs MGW & 3,500KGS MGW) to have their own registration number's when travelling in most European countries.. This INCLUDES caravans.

The only exceptions (currently) are Malta, Cyprus, Republic of Ireland and Spain.

Here is a walkthrough on how to proceed.

1. Click https://www.gov.uk/register-trailer-to-take-abroad

2. Click the green “START NOW” bar

   

   
   

3. It will ask if you have a trailer account. If you’re a new user, click NO.

4. Follow the steps through to the message You do not need to create a trailer ccount then click the green bar below that.

   

   
   

5. From there, sign in with your government gateway ID or create one and add your trailer details.

6. Hey Presto!

   

Breakaway Cable or Secondary Coupling? 🧐

Light trailers up to 750kg maximum laden weight are classed as cat O1 vehicles.

There is no requirement for O1 trailers to have a braking system but, they must be fitted with a ‘secondary coupling’ so that in the event of a breakaway or a primary coupling failure, the trailer is prevented from running away.  The secondary coupling has to be strong enough to restrain the fully laden trailer, and short enough to prevent the drawbar striking the ground, thereby retaining some residual steering.

If a cat O1 trailer is fitted with brakes, they must be operational on all wheels and it will be treated as a Cat O2.

Above 750kgs up to 3,500kgs, maximum laden weight, a trailer is a cat O2 vehicle.  All cat O2 trailers are required to have an operational braking system on all wheels and, it needs to be auto-reversible.  In general, this is achieved via an over-run (inertia) primary coupling, allied with auto-reverse mechanisms in each brake assembly, which detects when the wheels are operating in reverse mode.  This self releases when the trailer moves forward.

All O2 trailers must be fitted with a breakaway cable that, in the event of a detachment or primary coupling failure, will activate emergency braking, bringing the trailer to a standstill.  ALTERNATIVELY, (but only up to 1500kgs maximum laden weight), an O2 trailer can be fitted with a secondary coupling as per O1 trailers.

A secondary coupling restrains  the trailer and needs to be securely attached to the towing vehicles tow frame.

A breakaway cable allows the trailer to separate from the towing vehicle, but with the brakes fully applied, at which point the cable snaps and will need replacing.

Road Vehicles Lighting Regulations 1989 (and amendments).

Probably the most abused rule regarding lights & reflectors on trailers (including a-frame towed cars) is that regarding “Retro-Reflective Rear Triangles”.

Size is everything!

Specifically, each triangle should be red, be equilateral, 160mm along each edge (making it 140mm tall), and it must meet the photometric and colorimetric requirements laid down in EC regs or UNECE regs. It must carry either EC approval marks or UNECE approval marks including IIIA (class). https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:32008L0089

With positioning, the triangles must be fixed vertically with apex to the top and the apex needs to be no more than 400mm from the outside edge of the trailer body. A matching pair is required, fitted between 350mm and 1500mm from the ground. They must not be fitted to a moveable panel (which includes on to, or inside, a boot lid of a towed car).

The above rules most likely render the majority of marker boards supplied by a-frame suppliers, effectively illegal.

OTHER LIGHTS.

Category O1 (unbraked) and O2 (braked) trailers must replicate the lights of the towing vehicle, including (if 1600mm wide or over) white front position lamps. They must also carry the registration mark of the towing vehicle.

From Oct 2012, all braked trailers are required to be fitted with (at least one) operational reversing light(s).

There is NO requirement for an a-frame towed car to carry any additional signage but, it’s not illegal.

Additional sidelights or reflectors are required on trailers over 5mt long. (Boat trailers are exempt from this and from the requirement for front position lamps).