# The Road Vehicles (Display of Registration Marks) Regulations 2001, Paragraph 8


A border may be displayed on a registration plate where the border is—
(a) permanently marked;
(b) non-retroreflecting;
(c) of a single shade of non-retroreflecting colour without any design, pattern or texture;
(d) positioned no closer than 10 millimetres from the edge of any character of the registration mark;
(e) not positioned above any other markings; and
(f) no more than 5 millimetres in width.

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Source: https://www.legislation.gov.uk/uksi/2001/561/schedule/2/paragraph/8 (the official version)
Page: https://openlegislation.uk/road-vehicles-display-of-registration-marks-regulations-2001/schedule-2/paragraph-8
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.