The twelfth man these days is released to his county. I was at Lord's on Friday and Finn got back from Nottingham around 12:30 and took the field immediately. Took a wicket five minutes later as well. What they tend to do nowadays is to ask the county which is staging the test to find some talented local lads and give them the opportunity to get on a major stage.
Did you see the young lad who was practising with the team before start of play last week and ran straight into a bucket of whitewash? Bet his mum was pleased.
And remember Gary Pratt in 2005? Really pi$$ed off Ricky Ponting?
They usually select a young player from the host County who is a talented cricketer in the up and an excellent fielder - that player doesnt have to be a full County player, as in this young man's case. It can be a second XI or a junior side as the County team may be playing away from home.
Obviously this is a discussion betwnthe CB and the host County.
Ponting was annoyed because England seemed to have a policy of sending their bowlers off to have a little rest after a spell of bowling, and replacing them with specially skilled fielders, which seemed to some people like sharp practice. The rules were subsequently tightened up a bit.
I think the original 12th man is usually released to play for his county once he isn't selected to play.
I suppose they just need someone who is available- maybe a second or youth team player who isn't playing that day. In fact often several are used- maybe they take turns to be on standby.