All of London’s seedy poetry is there to see in the setting for TV thriller Slow Horses

In real life, the address that is the spies' fictional home reflects the author's original grimy, multilayered vision of the city

There is no blue plaque on the wall of 126Aldersgate, a narrow four-storey terrace above a fast-food grill, near London's Barbican, but it can't be too long before the building acquires some of the tourist cachet of 221BBaker Street.

The upper-floor offices are the fictional home to the rejected spies of Mick Herron's Slow Horses books, led by the sulphurous Jackson Lamb. They are also the star turn - alongside Gary Oldman and Kristin Scott Thomas - in the unmissable AppleTV+ dramatisation, which returns for a fourth series this week. One of the many joys of the drama is that it offers a vision of London that rarely makes it on to screen - that everyday layering of centuries of history and grime and struggle that seeps through the pores of the present. Herron describes the familiar medley" of those resolutely ungentrified streets perfectly, the weathered and the new; the social housing estate, and the eye hospital... [and] the complicated facade of an office block straight from an SF comic". The filming is a love letter to all that seedy poetry: The gauzy reflections in puddles that... after-hours made fast-food outlets and minicab offices brief flashes of wonder."