Why the stand-to-the-right rule on London Underground escalators?

Although they drive on the left and walk on the left on crowded pavements, Londoners stand on the right on Tube station escalators and the reason is historic.

The first successful London Tube escalator, at Earls Court Station, required passengers to disembark diagonally to the left.

Therefore it made sense to stand to the right while those who chose to climb could do so on the left and exit without having to cut through the line of non-climbers, otherwise chaos would have ensued.

Even after escalator design changed so that everyone headed off in a straight line, the stand right, walk left convention remained.

In 2016, that was changed in an experiment at Holborn Station, one of London Underground's busiest, with some of its longest escalators.

During morning rush hour, commuters on two upward-moving escalators were asked to stand on both right and left sides, while those on a third upward moving escalator were able to climb or stand, as before.

Outrage followed, but the experiment proved that during peak hour, the standing-only rule got commuters through the station and on their way more quickly.