The Wasps No.8 was given a three-week ban earlier this month after being found guilty of striking North with his knee and/or shin after the Saints wing scored his second try in an Aviva Premiership fixture at Franklin’s Gardens on March 27.
In the initial judgement, Sir James Dingemans said: “This was a three week ban on the basis that no intention was found.
“However, there was recklessness meaning that, notwithstanding the harm, it was a low entry point of four weeks with mitigation of one week to reflect his previous clean playing record.”
Hughes missed the Champions Cup quarter-final defeat at Toulon last Sunday, but Wasps have now been told their appeal has been successful, with new evidence having emerged.
Appeal panel Chair Jeremy Summers said: “The appeal panel considered it appropriate to hear the matter afresh.
“Having done so and having had the advantage of evidence not before the original panel, it concluded that no act of foul play took place in that the incident occurred accidently.”
Wasps boss Dai Young had felt referee Craig Maxwell-Keys’ decision to red card Hughes was ‘harsh’, but Saints director of rugby Jim Mallinder backed the official.
And after Hughes was hit with the ban, Mallinder said: “I said at the time I think it was a red card offence. I still do. Therefore the disciplinary process has taken place and that’s what he’s got.
“My opinion is what it is. You’ve got to be very, very careful. George North scored a try and therefore there wasn’t much anybody could do about that.
“You’ve got to make as much effort as you can to get away from that incident. We don’t want that happening again.”
Wales wing North, who also suffered concussions in autumn and Six Nations internationals, has since seen a neurologist and been advised to rest until the end of April.
He will be reassessed at the start of May.