Allegations of illegally tampering with the ball are nothing new. They date to at least 1921, when the England captain J.W.H.T. Douglas threatened to report his Australian opponent Arthur Mailey for using resin to grip the ball more firmly; Mailey is said to have countered by saying that Douglas had picked at the ball with his thumbnail.

In the last 25 years, international cricketers have been punished for tampering with the ball in many ways — including keeping dirt in their pockets, rubbing a cough lozenge on the surface, scuffing the ball on the zips of their trousers and even biting the ball, which the Pakistan captain Shahid Afridi was found guilty of in 2010.

Even mints and sweets can be used for nefarious ends. When England won the Ashes, a competition between England and Australia, in 2005, the English player Marcus Trescothick later admitted that he had applied saliva to one side of the ball after sucking mints. That tactic is thought to affect the flight of the ball by making one side slightly shinier.

And when Australia last hosted South Africa in a series in 2016, the South Africa captain Faf du Plessis was caught sucking mints and then using his saliva to polish the ball on one side, again to try to alter the flight and bounce. He was later fined his match fee.

The incidents highlight how hard it is to eliminate ball-tampering, which is notoriously difficult to prove — adding saliva is legal, but doing so while sucking mints is not.

Some have suggested that the laws should be revised, perhaps by legalizing some aspects of treating the ball, like using saliva after sucking candy or mints, that are especially hard to police.

Yet the actions of Bancroft — and, especially, Smith in instructing him — are seen as falling well beyond the normal ambiguity of the law. The Australians’ actions amounted to nothing less than flagrant cheating.