# Regulation (EC) No 661/2009 of the European Parliament and of the Council of 13 July 2009 concerning type-approval requirements for the general safety of motor vehicles, their trailers and systems, components and separate technical units intended therefor (Text with EEA relevance), Division ( f ): Where it is declared by the vehicle manufacturer that a vehicle is suitable for towing loads (point 1.9 of Annex I to Commission Implementing Regulation (EU) 2020/683) and any part of a suitable mechanical coupling device, whether fitted or not to the type of motor-vehicle, could (partly) obscure any lighting component and/or the space for mounting and fixing the rear registration plate, the following shall apply:

Extent: E+W+S+N.I.

the motor-vehicle's user instructions (e.g. owner's manual, vehicle handbook) shall clearly specify that installation of a mechanical coupling device that cannot be easily removed or repositioned is not permitted;
the instructions shall also clearly specify that, when fitted, a mechanical coupling device must always be removed or repositioned when it is not in use; and
in the case of vehicle system type-approval according to UN Regulation 55, it shall be ensured that the removal, repositioning and/or alternate location provisions are also fully complied with as regards lighting installation and space for mounting and fixing the rear registration plate.

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Source: https://www.legislation.gov.uk/eur/2009/661/annex/IV/annotations/1/annotation/9 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-661/annex-IV/annotations/1/annotation/9
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.