Police have clarified the Highway Code rules on undertaking, confirming that overtaking on the left is lawful only in certain circumstances, such as congested traffic, and that doing so otherwise could lead to prosecution for careless driving.
The clarification follows a question from a motorist on the official 'ask the police' website, which is administered by forces around the UK. The driver asked: "Can I overtake on the left (undertake)?"
What the Highway Code says
In response, police first cited rule 163 of the Highway Code, which relates to driving on non-motorways. It states: "Only overtake on the left if the vehicle in front is signalling to turn right, and there is room to do so. Stay in your lane if traffic is moving slowly in queues. If the queue on your right is moving more slowly than you are, you may pass on the left."
For motorways, police cited rule 268, which states: "Do not overtake on the left or move to a lane on your left to overtake. In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right. Do not weave in and out of lanes to overtake."
Legal consequences and safety warning
Police added: "Overtaking on the left is lawful if done in accordance with the above guidance. However, whilst there is no specific offence of overtaking on the left, if a driver undertook another vehicle, other than in the circumstances described above e.g. in the case of someone hogging lane two on a motorway, they may be prosecuted for careless driving."
Officers also urged drivers to take "extreme care" when overtaking another motorist on the left, explaining that it could expose them to a number of dangers. For example, police suggested other drivers may not see you as you are overtaking and so may suddenly move back to the left.
