Last week, as with many cycling fans, I was watching the culmination of this year’s Vuelta a Espana. Friday’s stage, from Avila to Toledo, saw a huge crash on a sharp corner. Numerous riders hit the deck, including the race leader, Primoz Roglic. As Roglic and others were tended to by medics, one of the rival teams, Movistar, decided to pick up the pace. Their rider, the world champion, Alejandro Valverde, was in second place and this seemed an ideal opportunity to take the race lead.

Except that cycling, as with many sports, is one full of unwritten rules. Even when drug taking got to the Lance Armstrong levels of blood transfusions, it still remained a sacrosanct rule that you didn’t attack the race leader when he has had a crash. Although Roglic eventually recovered, the fallout from the episode continued long past the finish line. Movistar first claimed that it had always just been part of their plan to attack at that particular point. But as opprobrium continued, the team eventually apologised, saying they wished that there was a ‘sole set of criteria … on how to proceed when such situations arise’.

Unwritten rules have, for many years, been what has helped make the world go round. Their existence in sport probably goes back to many being established in a Victorian era when an underlying sense of fair play prevailed. Increasingly, however, that sort of Corinthian ethos has buckled under pressure, with people not just pushing the unwritten rules, but bending them to breaking point.

As in sport, so in life. The UK (along with, I think, Israel and New Zealand) is one of the few countries in the world not to have a written constitution. Instead, we have for many years got by with a hodgepodge of acts of Parliament, court judgments and conventions. That idea works as long as everyone sticks to those. When they don’t, the whole system is in danger of falling down: ending up, as with the case of prorogation in the Supreme Court, with judges called in to rule on what politicians can and can’t do.

Last year, you may remember, someone attempted to steal the Magna Carta from Salisbury Cathedral. Looking back, the image of those holes smashed in the protective glass feels increasingly symbolic of the way our way of doing politics is going. Whatever your views on Brexit, there’s something in how events are playing out that should give pause.

Perhaps these are examples of a larger historical moment, of the old world bumping up against the new. But if we no longer feel the need to stick to unwritten rules, what does that say about who we are?