There are no speed-limit signs on the road. In England, Scotland and Northern Ireland how is a 30 mph limit generally indicated?

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There are no speed-limit signs on the road. In England, Scotland and Northern Ireland how is a 30 mph limit generally indicated?

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In England, Scotland and Northern Ireland, there’s a 30 mph speed limit where there are street lights unless signs show another limit.
In Wales street lights indicate the limit is 20 mph unless signs show otherwise.