If there was ever any doubt about it, Broad has confirmed he knows he nicked it but he claims he didn't "cheat". Lehmann has an opposite view :
Stuart Broad said:
It wasn't as clear-cut as everyone had thought, although I knew I'd hit it
Darren Lehmann said:
Certainly our players haven't forgotten, they're calling him everything under the sun as they go past so I would hope the Australian public are the same because that was just blatant cheating
BBC Sport - Ashes 2013: Stuart Broad is a blatant cheat - Darren Lehmann
I agree with Lehmann, this whole culture of "walking" or "not a walker" is just bull's hit, it is a way of cheating but not being seen or called as a cheat. If you brush a ball on the snooker table and the umpire doesn't notice but you know it's a foul, you should call it or you are cheating. If you are playing Bridge/any card game where you follow suit, and don't follow suit but instead trump, you are cheating if you know it and don't come clean. I've known people not realise, that is a mistake on their part, but if they do it knowingly then they cheat. If someone playing crib is deliberately not pegging carefully they may claim it is up to their opponent to check their pegging, it is cheating though.
In the unlikely event you deliberately handle the ball at football, and are not the keeper, if you don't call it you are cheating. The latter is a harder comparison as people deliberately handling the ball are hardly likely to confess, but I suppose in a way it is comparable because you know what you should do and don't do it so are trying to "gain an unfair advantage" aka cheating.
It's all very well Broad talking "clear cut", he knew he was out. In the Agar incident it was erroneous umpiring at worst, questionable re whether any part of his foot were behind the line. He wouldn't know, not that we're accusing him of cheating, but if England and the fans point at that as crucial well at least that was an HONEST mistake, not a DISHONEST/cheating one.
So England are the immoral victors, deserved or not there is that lack of sportsmanship. Excusing it by "well they do it" is not really an excuse.