Photographer Bob Mazzer spent two decades commuting to work and back on the tube. As he travelled, he used his Leica M4 and his own unique perspective to capture Londoners, commuters and tourists as they journeyed through the capital's network of tunnels.Here is a small collection of his work, some of which was first shown in a GLC exhibition at the Royal Festival Hall in the 1980s.(Photos: Bob Mazzer, via Telegraph