When I was a trade union committee member in the 1990s, my experienced colleagues drummed a lesson into me: never get involved in a dispute unless you know how you are likely to emerge at the other end.

It is not clear that the leaders of Britain’s postal workers, who staged a two-day strike last week, understood what effect their action would have, but others did. Many people inconvenienced by the strike – companies whose payments were stuck in the mail, parents who could not submit their children’s school applications – no doubt resolved to use the internet in future.