In Canonbury, this sign advertises the services of John C Mather, builder and decorator, plumber and gas and hot water fitter. Among all those skills, he offered one area of particular expertise: Sanitary work a speciality.
At first glance, the sign is rather practical, emphasising clarity over artistry. Yet a closer look shows every letter has some rather nice shadowing in red. There's also a fun little loop in the initial letter of 'Mather'. When it was fresh, this must have looked pretty jaunty.
And it has an excuse for being a little worn and tired: it's pretty old. As Sebastien of Painted Signs & Mosaics discovered, Mather was in business between 1906 and 1941. The sign was at the entrance to his yard; he also had offices in nearby Northampton Street.