Explanation: You should overtake only when it's really necessary and you can see it's clear ahead. Look out for road signs and markings that show it's illegal or would be unsafe to overtake; for example, approaching junctions or bends. In many cases, overtaking is unlikely to significantly improve your journey time.
Category: Hazard awareness
References: The official DVSA guide to driving: section 7, Highway code: rule 162-167