Here’s what UK law and the Highway Code say:
✅ When overtaking in a 30 mph zone may be legal:
There are no solid white lines in the centre of the road.
There are no signs prohibiting overtaking.
You can complete the manoeuvre safely and without speeding.
You’re not near pedestrian crossings, junctions, bends, or humps that obstruct visibility.
❌ Overtaking is illegal or dangerous if:
There’s a solid white centre line (Rule 129, Highway Code).
You’re approaching or on a pedestrian crossing (Rule 191).
You’re near a junction, on a bend, or a hill where you can’t see ahead clearly (Rule 162).
You’re passing a school zone, or near parked cars with limited visibility.
Important context:
Most 30 mph zones in the UK are urban or residential, with high pedestrian activity, parked cars, and narrow lanes.
Overtaking in these areas is usually unnecessary and can be seen as careless or dangerous driving, which is an offence.
Conclusion:
🔹 Legal? Sometimes — if the road layout and visibility make it safe.
🔹 Recommended? Rarely — especially in towns, villages, or near schools.
🔹 Risk of penalty? Yes, if the overtake is judged unsafe or leads to an accident.
If you have a specific scenario (e.g. overtaking a cyclist, slow-moving vehicle), I can give more tailored guidance.