You MUST obey signs giving orders. These signs are mostly in

Explanation: There are three basic types of traffic sign, those that warn, inform or give orders. Generally, triangular signs warn, rectangular ones give information or directions, and circular signs usually give orders. An exception is the eight-sided 'STOP' sign.

Category: Road and Traffic Signs

References: The Official DVSA Guide to Driving: Section 6, Highway Code: Page 106, Know Your Traffic Signs: Page 9, Know Your Traffic Signs: Page 16