Joe Hart's spell at Birmingham was vital to him reaching the level required to be England's number one, according to his former boss Alex McLeish.
The Manchester City star spent last season on loan at St Andrew's, where his superb performances were key to the Blues achieving a ninth-placed finish in the Premier League and earned him a place in Fabio Capello's World Cup squad.
Hart has now established himself as England's top goalkeeper, but McLeish revealed: "We looked at Joe Hart's game last year after the first few games. I spoke to (Birmingham goalkeeping coach) Dave Watson and said 'there are a few things we've simply got to work on'."
He added: "At the time, one of the things was that Joe was punching everything.
"I said 'Joe, you are 6ft 4in tall, you're the only guy who can use your hands in the box'. Dave, myself and Joe saw some video stuff and we thought it was a wee habit he had just got into.
"We don't know where he acquired it but it was in his game and maybe that is why Mark Hughes decided to go for Shay Given (at Manchester City)."
McLeish recalled: "In our next game, Maik Taylor played against Man City, when Joe couldn't play, had a shut-out and rightly felt he should be in the next game.
"I said 'no, Joe is out by default, he is back in, he is my number one for the season'.
"Joe took a lot of confidence from that and the fact Dave had been working with him in that interim two weeks between the Man City game and the next one.
"I remember a big cross coming into the box and Joe took it, and I could see the chest puffing out and the head going up and he never looked back and is now England's current first choice."