reddy brown adult centipede with 15 pairs of legs - those at the rear are elongated. Approx 20mm in length.
No interactions present.
Not a clear enough picture to be 100% sure but quite unlikely to be much else at 20mm unless Lithobius pilicornis but last legs indicate that it is not
Lat/Lng: 51.41964, -0.03891
OS grid ref: TQ364707
Sunny autumnal day on Green Chain Walk, Beckenham, Kent (Greater London).