How does a great institution die? In the same two stages as Hemingway believed people went bankrupt: gradually, then suddenly. Entire decades may pass in which a vital service or a venerable organisation undergoes deep cuts, blundering reforms, and erosion as slow and unremarkable as that of a coastline. Then one day – snap! It breaks, for ever.

This is what’s happening right now to one of our oldest and most essential services. An institution that binds the country together, and daily and almost invisibly helps to define it.

I’m not talking about the NHS, the BBC or state schools. Those parts of society make far more dramatic incursions into our lives. The hospital that delivered your baby, the black screen that brought you Del Boy and Rodney, the teacher who coaxed you through your ABCs: no wonder any big change prompts loud debate. Not so the flap in your front door through which burst bright cards at Christmas, those magazines and guilty eBay purchases, the sad tidings from family on the other side of the world. Not the system that devised the postcode in which you are right now, nor the 115,000 jolly red boxes that stake out the territory of the UK.

The Royal Mail dates back more than 500 years to the reign of Henry VIII. For most of our lifetimes it promised to get a first-class letter from your nearest postbox in Hove to your intended’s front door in Aberdeen by the next day – and it kept it. That is a piece of public sector magic, less dramatic than life-saving surgery certainly, but based upon vast infrastructure and a formidable workforce ethic. WH Auden knew that, and marvelled at the night train carrying “Letters for the rich, letters for the poor/ The shop at the corner, the girl next door.” Even Margaret Thatcher understood it, which is why that inveterate privatiser snubbed all those people in the 1980s urging her to flog off our postal........

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