Former Manchester City goalkeeper Tony Coton says Joe Hart needs a quality understudy to push him to reach his potential. Coton's £500,000 move across ­Manchester from City to Manchester United in 1996 prompted an angry fan backlash.

But even though he didn't play a first-team game for United, his sheer presence prompted Peter Schmeichel to respond with a string of performances that helped land a Premier League and FA Cup Double.

Coton said: "The best piece of ­advice I ever heard came from a tennis coach, who said that to get to No.1 in the world and stay there you always have to train like you're No.2.

"What he meant was that it is hard to get to the top - but even harder to stay there. When you are the best, complacency can creep in. You don't notice that it's ­happening at first and, when you do, it can be too late.

"Hart is the best keeper at City and he's also the best English keeper around by some distance. But he faces no ­competition for club or country.

"He goes into every game ­knowing that he will stay in the team ­regardless of how he plays that particular week. It's the same when he plays for England."