Article one of law three in the rules of football states simply: 'A match may not start or continue if either team has fewer than seven players.'
It's not something invoked too often in what is an 11-a-side sport but it was invoked precisely 15 years ago in one of the game's strangest abandonments.
The Football League Division One fixture between Sheffield United and West Bromwich Albion on March 16, 2002 at Bramall Lane was meant to be pretty run-of-the-mill.
The Baggies were in third position but not looking too likely to catch their local rivals Wolverhampton Wanderers and snatch the second automatic ticket to the Premier League.