I’ve just finished walking across all of the UK’s 15 national parks and 69 cities: the equivalent of the length of Britain and then some. Without a doubt, the best part of my journey was my 18-hour, 56km leg across London: from Hinchley Wood in the south-west, through the centre of the city and all the way to Grange Hill in the north-east. The UK has many brilliant cities, but none compare to London’s diversity, omnipotence and sheer scale.