On the face of it, the Afghan data breach is very bad indeed. It is arguably the worst leak of secret UK government names since the former MI6 officer Richard Tomlinson went rogue and published a list online containing dozens of names of MI6 officers in 1999.

The UK’s previous government set up a secret immigration route for Afghans affected by a data breach three years ago and then kept it secret from the British public, Defence Secretary John Healey said.