Hands up if you know how many runs South Africa won the third Test against Australia by? Or if you knew what the score was on day three? Or if, prior to Saturday, you knew there was a third Test going on?

Whatever your view on the ball-tampering saga - funny, pathetic, reprehensible or a mix of all three - it's impossible to deny it has overshadowed a potentially great series.

Captain Steve Smith and Cameron Bancroft's admission on Saturday that Australia had a premeditated plan to tamper with the ball turned the Test into a circus.

The two have been sanctioned by the International Cricket Council, but that will only be the beginning of the fall-out.

So what is the reason for ball-tampering? Is it as serious as it has been made out to be? And have Australia, with their talk of "the line" and knowing where it's drawn, brought extra scorn on themselves?

Australia's ball-tampering 'a massive kick in the nuts' for fans - Flintoff

What is ball-tampering?

Level two offences - of which Smith and Bancroft were found guilty - are serious. There are four levels under the ICC's code of conduct, which takes guidance from a cricket committee that includes former players and umpiring representatives, with four being the highest in terms of severity.

And ball-tampering - which often results in a team being able to utilise reverse swing, where the ball moves through the air at high speed towards a batsman - happens more often than people realise.

Roughing up one side of the ball can be achieved by, say, a fielder out on the boundary throwing the ball in on the bounce into a rough part of the square. Sometimes, those stationed close might bounce the ball to the keeper.

While throwing the ball on the bounce is not illegal, umpires are quick to warn a fielding side if they believe it is being done to alter the state of the ball.