Stuart Lancaster has pledged to make it clear to Dylan Hartley that any more lapses in discipline could blow England's Six Nations rugby chances.
Hartley was hit with a three-week ban after being sent off for elbowing Leicester centre Matt Smith in Northampton's 23-19 Premiership victory on December 20.
The 28-year-old hooker's latest ban took his career suspension tally to 50 weeks, adding to a rap-sheet including eye-gouging, biting, punching and swearing.
Lancaster will remind Hartley of his responsibilities to hold his temper, especially when England open their Six Nations campaign in the pressure-cooker Millennium Stadium atmosphere against Wales on Friday, February 6.
"(England forwards coach) Graham (Rowntree) spoke to him and I'm going to speak to him in the camp," said Lancaster.
"If you give away dumb penalties clearly it's going to compromise your chances of winning, particularly against Wales who have Leigh Halfpenny who can kick goals from everywhere.
"I'll be making it absolutely crystal clear to Dylan, one to one, but also the team, that discipline has to be top-notch."
England start the year when they host the World Cup by returning to Cardiff for the first time since their record 30-3 defeat to Wales in 2013.
That crushing loss handed Warren Gatland's men the Six Nations title, and Lancaster is not about to allow indiscipline from hooker Hartley, or anyone else, to derail this season's campaign.
The England boss had vowed Hartley was in the "last-chance saloon" after his red card for swearing at referee Wayne Barnes during the 2013 Premiership final.
That dismissal led to an 11-week suspension that cost Hartley his place in the British and Irish Lions tour to Australia.
Lancaster was furious with Hartley for conceding a cheap yellow card in England's 31-28 defeat to South Africa in November, and will not accept any repeat.
"I remember going into the game in Wales two years ago, and through penalties we ended up 9-3 down going into halftime which then extended to 12-3," said Lancaster.
"And then before you knew it the first try came.
"I'll speak to Dylan individually about all that."
Lancaster named a 34-man Six Nations training squad on Wednesday, bringing both Danny Cipriani and 36-year-old Nick Easter in from the cold.
Harlequins No.8 Easter is back in an England squad for the first time since the 2011 World Cup.
Backs:
Brad Barritt, Mike Brown, Luther Burrell, Danny Care, Danny Cipriani, Kyle Eastmond, Owen Farrell, George Ford, Alex Goode, Jonathan Joseph, Jonny May, Stephen Myler, Jack Nowell, Billy Twelvetrees, Anthony Watson, Richard Wigglesworth, Ben Youngs.
Forwards:
Dave Attwood, Calum Clark, Dan Cole, Alex Corbisiero, Nick Easter, Dylan Hartley, James Haskell, Graham Kitchener, George Kruis, Joe Marler, Geoff Parling, Chris Robshaw (capt), Billy Vunipola, Mako Vunipola, David Wilson, Tom Wood, Tom Youngs
Share
