Does pressing the pedestrian crossing button actually do anything?

The BBC has published an informative article on this subject.

Short answer: It depends.

At a standalone pedestrian crossing, unconnected to a junction, the button will turn a traffic light red.

At a junction it is more complicated. At night, the button does act to stop the traffic, but only between the hours of midnight and 07:00. In the daytime, the button has no effect.
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