The secrets of London by postcode: N (North)

How Rod Stewart kept his hair in place, why the BBC gave its presenters electric shocks and what Paul Gascoigne shot with an air rifle: this month’s London postcode area is N – buckle up for another trivia-packed tour…

• The first run that cabbies have to learn for the Knowledge is Manor House Tube station to Gibson Square. Their task, as with any journey, is to take the most direct route possible – this is called being ‘on the cotton’, because the route will follow the straight line mapped by an imaginary piece of thread stretched between the two points on the map.

• The Great Northern Hotel at King’s Cross gets its unusual shape from the River Fleet. The road there was curved because it followed the river (which is now underground), so when the Great Northern was constructed (1854 – London’s first station hotel) the building followed the road. Soundproofing between floors was achieved by filling the gaps with clinker (a waste product that results from burning coal).