11.—(1) The colours prescribed for signs must conform to British Standard BS EN 12899-1:2007(1).
(2) Paragraph (1) does not apply—
(a)if alternative provision is made elsewhere in these Regulations in relation to a sign; or
(b)to the extent it is provided that part of a sign may be of any, or any contrasting, colour.
Publication date 30th April 2008 (ISBN 9780580813474): corrigenda May 2008, June 2009, October 2011 and May 2013.