Spies never stop being spies, even when they’ve been out of the game for a while, and even when they know the game is up. Season two of Slow Horses (AppleTV+) starts with an old geezer standing behind the counter of a Soho sex shop, minding his own business – until he recognises a passerby and immediately sets off in pursuit, tailing the mystery man to a railway station, on to a train, then through the rain to catch a rail replacement bus bound for Oxford Parkway. On the bus, the sex shop proprietor begins to feel unwell, but before he drops dead, he types a single codeword into his phone and hides the device down the side of his seat. The man he was following gets away.