London - Fiery England hooker Dylan Hartley must keep playing "on the edge" but has to retain his composure against opponents who see him as an easy target to wind-up, according to England World Cup winner Neil Back.
Hartley's on-field indiscretions have been a regular occurrence in the 28-year-old's career, a lack of discipline costing him lengthy bans at various times, including a place on the British and Irish Lions tour of Australia two years ago.
Back fears Hartley, capped 61 times since making his international debut in 2008, could once again see the red mist descend when he lines up for England in what is sure to be a bone-jarring clash with old enemies Wales in Cardiff on Friday.
"The best players in the world deal with pressure really well. Metaphorically if he's punched in the face, he has to wipe the blood off, smile at the guy that did it and get on with the next job," Back said.
Hartley has been seeing a sports psychologist in a bid to avoid further trouble and the Six Nations championship provides an acid test for a player who needs to show England coach Stuart Lancaster that he has learned from his mistakes.
"You don't want to be playing with 14 men.
"He's got to play right to the edge of the law, but stay to the right side of it and that takes discipline and if he can't do that he is going to let himself down and ultimately his team mates and country," Back, part of England's triumphant 2003 World Cup side, said.
"He is not alone. England will be targeted and you can't let yourself or your team down.
"Easier said than done but that's what he's got to do because the incidents that have happened over his career...he has got to make them less frequent."
Hartley's misdemeanours include serving a 26-week ban for eye-gouging in 2007 and an eight-week ban for biting Ireland flanker Stephen Ferris in the 2012 Six Nations.
He was shown a red card for swearing at the referee in the Premiership final in 2013, an indiscretion which cost him a place on the Lions tour and in December he was suspended for three weeks for elbowing Leicester's Matt Smith in a Premiership match.