This sign is on Bermondsey Street, SE1, and reads 'Estabd 1857 - Thomson Bros Ltd - PAPER'. It's not the most decorative example, and the fitting of the bold word 'paper' into this narrow bit of side wall is a little awkward. However, even now it's scuffed and faded, it has the virtues of being clear and bold.
The firm proves rather elusive: in the 1902 Post Office Directory, for example, there is no Thomson Bros on Bermondsey Street although there is a listing for 'Thomson Brothers Limited, wholesale stationers' at 49 Knightrider Street, EC. It may be that one of the tanneries here was also an agent for Thomson Bros; the common name also doesn't help in tracking them down. If anyone has more information, I would love to know!