Regulatory sign
Keep left sign
What does the Keep left sign mean?
You must keep to the left of the sign. It's a blue circle, so it's a mandatory instruction rather than advice.
Also known as: Keep left arrow, Keep right (reversed)
What it means
Traffic must pass to the left of the sign. With the arrow reversed, it means keep right.
You'll typically see it on traffic islands and bollards, showing which side you must pass.
Don't confuse it with the sign with arrows pointing both ways. That one means vehicles may pass either side to reach the same destination.
Rules to know
The sign means keep left; with the symbol reversed, it means keep right.
Know Your Traffic Signs, p. 19
A blue circle generally gives a positive (mandatory) instruction.
Know Your Traffic Signs, p. 16
Common mistakes
Mistake: Passing on the right of an island because it looks quicker.
Instead: The sign is mandatory: you must pass on the side the arrow shows.
Test yourself
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© Crown copyright. Free to reuse under the Open Government Licence v3.0, as long as the sign is reproduced accurately and not in a misleading context.
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Sources
- Know Your Traffic Signs (Department for Transport, Sixth edition, 2023), Regulatory signs, pp. 16 and 19
Sign image: Department for Transport, Traffic sign images (diagram 610). © Crown copyright, reused under the Open Government Licence v3.0.
Checked against these sources and reviewed by Bikash Thapa, full UK driving licence holder. Last reviewed 4 October 2026. This page explains the sign in our own words; for the full rules, see The Highway Code. How we source and check content