Blue circular signs form one half of the order sign group, used specifically to tell drivers what they must do.
Recognising the blue circle helps you quickly identify a positive instruction that has legal force.
What this sign system means
A blue background with a white symbol on a circular sign indicates a mandatory instruction, such as turn left ahead or mini roundabout.
These differ from red ringed prohibitory signs because they tell you what action to take, rather than what to avoid.
What to do when you see it
Carry out the instruction shown, since blue circular signs are compulsory and not simply suggestions.
- Identify the specific instruction shown by the white symbol
- Follow the required direction, lane or action promptly
- Treat the instruction as legally binding, not advisory
- Watch for blue circles combined with arrows at complex junctions
How this sign is tested
The theory test regularly checks recognition of common blue circle signs such as turn left, ahead only and minimum speed limits.
You may be asked to identify the correct action required by a specific mandatory sign.
Common mistakes
Learners sometimes confuse blue mandatory signs with blue informational signs used on motorways, which are a different category.
Ignoring a mandatory direction because it seems inconvenient is a serious and common error.
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Practise road sign questionsFrequently asked questions
What colour tells me a sign is mandatory
A blue circular background indicates a mandatory instruction that you must follow.
Is a blue circle sign the same as a blue rectangular motorway sign
No, blue rectangles are generally for motorway direction information, while blue circles give mandatory instructions.
Can I ignore a blue circle sign if the road looks clear
No, mandatory signs are legal instructions and must be followed regardless of how the road appears.