Northampton look set to mount a robust defence of their captain Dylan Hartley after he was sent off for elbowing Leicester centre Matt Smith in the face during their 23-19 Aviva Premiership victory at Franklin's Gardens.

Hartley could miss at least the start of England's RBS 6 Nations campaign following the latest episode in a career scarred by repeated disciplinary episodes.

He was handed a 26-week ban for eye-gouging in 2007, and an 11-week suspension for verbally abusing referee Wayne Barnes during the 2013 Aviva Premiership final against Leicester.

That latter ban led to him missing the British and Irish Lions tour of Australia, and Rugby Football Union disciplinary chiefs could easily take a dim view of his latest indiscretion.

It happened after just 17 minutes of a titanic east midlands derby the Saints won thanks to substitute Jamie Elliott's 77th-minute try that fly-half Stephen Myler converted from the touchline.

Referee JP Doyle initially seemed happy to award Hartley a yellow card, but television match official Sean Davey urged Doyle to watch further replays, and he responded by sending 61 times-capped Hartley off.

"It was disappointing," Northampton rugby director Jim Mallinder said.

"Dylan has got to keep his arms down, but he was being held and I don't know there was any malice in it.

"The nature of the game didn't justify a red card. I think Smith went down pretty easily, to be honest, which was disappointing.

"It is a tough game. That 80 minutes of rugby was hard, physical, with some great tackles, but I don't think there was any malice in that. I think JP's initial reaction of the yellow card would have been the correct decision."

England open their Six Nations campaign against Wales in Cardiff on February 6, and given 28-year-old Hartley's poor record - biting and punching offences also appear on his charge-sheet - another lengthy suspension appears likely, with a disciplinary hearing set to be convened before Christmas.

"It's a tough game, and Dylan plays to the edge. You wouldn't change Dylan. He is competitive," Mallinder added.

"It is a difficult one. I think he should have kept his arms down - we are not saying that what he did was right - but what I am probably saying is that the opposition made it a lot easier, and a yellow card was sufficient."

Saints had earlier delivered tries for prop Alex Waller and replacement Ben Foden, plus two Myler penalties, with the lead changing hands five times during a pulsating second period.

Wing Vereniki Goneva claimed two touchdowns for Tigers, which followed an early penalty try, while Owen Williams and Freddie Burns each kicked a conversion.

Asked for his reaction to the Hartley dismissal, Leicester boss Richard Cockerill said: "If you strike someone in the face you are liable to get yourself in trouble. That's the nature of it.

"You would have thought he might have learnt a lesson by now. That's just the way it is."

And reflecting on Tigers' performance, Cockerill added: "I am disappointed with how we managed the second half. We got what we deserved, probably.

"You have to control the field position and get the pack in the right areas, and we didn't do that at all.

"Defensively, we were poor. We were too narrow, and it will be interesting when we have a look on Monday morning that one side with one less back can create opportunities in the wide channels against us. That's not right.

"They outplayed us in the second-half. There is no point in beating about the bush. We seemed to go awol at times in defence."

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