Road Traffic Act 1988, sec. 36.
Butterworths, Seventh Edition has this to say:
"Section 36 applies to any sign which indicates a statutory prohibition, restriction or requirement, or to any traffic sign where it is expressly provided by or under the Road Traffic Act 1988 or the Road Traffic Regulation Act 1984 that s36 shall apply to the sign; such express provision has been made by the Traffic Signs Regulations and General Directions 1994, reg 10."
Blackstones Police Manual, Road Traffic 2004 goes further and in chapter 10 section 3 (Failing to comply with a traffic sign) para 2 it says:
"Failing to comply with signs where s. 36 of the Road Traffic Act 1988 is specifically referred to as applying to them (e.g. those listed in reg. 10 of the Traffic Signs Regulations and General Directions 2002)."
It further lists a number of the signs that are listed in reg. 10 of TSRGD 2002. "No U-Turns" is amonst them.
-- Mark Foster, Brighton, Suslove, UK PGP Fingerprint: 3342 C02C 7BE8 3FE4 AAC5 8BB2 03B7 9263 DDF2 04C1 -------------------------------------------------- "There are no such useless words as...'I didn't have a chance.'" Driving, HMSO