On Sunday night we partied: we jumped, danced, cheered, we cried as the exquisite petals of Thomas Heatherwick’s Olympic cauldron faded into darkness, turning a stadium full of victorious, shining Olympians back into a crowd of a physically ultra-tuned young men and women, pumped up with enough sex drive to populate several small countries. No doubt the Olympic Village created its very own cauldron that night and dawn, as thousands of locationships began and ended amidst polished meetings of flesh.

And now that the party is over Britain has POF, a curious divergence from the cruel post-traumatic stress suffered by those going through the aftermath of war, violence, and disaster. This version, post-Olympic Fantasy, has a strange pathology, and for anyone from outside London it is important to know how to recognise this disorder, so that you can stay on your feet and alive. We have become a metropolis peopled by millions of inhabitants who are doing their very own Olympic version of air guitar in the shower, on a grand scale. Joggers, cyclists, roller-bladers, and people on all kinds of thigh-powered wheels, are now plugged into David Bowie’s Heroes, and starting their own, personal 100 metres, 200 metres, Keirin, Omnium, sprint, take your pick, but our streets are no longer streets. We have been transformed into a vast and stretching series of stadia in which the good burghers are bidding for immortality, regardless of pushchairs, the elderly, buses and lorries with blind-spots, and small dogs shitting on roadsides. The start lines are formed predominantly at traffic lights, and the participants will pick their opponents partly through prejudice, but largely on the basis of who can definitely be beaten. Man in White Van is going through a lot of stick at London traffic lights at the moment.

So, if you are coming to this funny wet and green island, to visit, for fun, or because you are preparing for the Paralympics, be very careful at traffic lights, when crossing all cycle lanes, on any pavement wide enough to become a fantasy velodrome in the mind’s eye of tens of thousands of gimlet-eyed cyclists, actually on pretty much any flat surface. We have become a nation of champions, for now, and the British are Olympian in another discipline beyond those played out so gloriously over the past fortnight. We are fantasists of the highest order, so tread carefully or you may be flattened by our dream – with apologies to William Butler Yeats.