That dates you a bit they were not a new thing when I fist started attending over 50 years ago - must have been introduced sometime in the '60s I think
Unfortunately, I am dated! Just checked on Wikipedia, and it seems that one sub per team per match was allowed from 1965-66, but even that only to replace an injured player. It was, if course, hard to prove that any player is not injured, if he goes down and says he is.
Sorry winged avenger, I think Barry was the first sub to go on rather than being subbed. He replaced the injured Brian Jackson on October 29th, 1965. Football League rules were changed at the start of the season to allow one substitute to be used but only as an injury replacement. Unfortunately he wasn’t able to influence the result as the Reds were defeated 5-1 by Doncaster Rovers at Oakwell. Amazingly, no further substitutions were made for the rest of the season. Bob Earnshaw became the second substitute on 10 September the following season in a 2-1 victory versus Luton Town at Oakwell. Earnshaw scored during that game and the other scorer was …..Barry Murphy, scoring one of the three goals he scored for us. The substitute rule was changed in the 1967-68 season to allow tactical substitutions.
December 1989 Jay at Bournemouth. He gave the linesman some abuse for allowing one of Bournemouth's goals. The linesman called the ref over and he sent him off! I couldn't remember the score but have checked and we lost 2-1.
I thought if he was off the field he could stand where he wanted as long as he had a different colour bib to any of the teams playing