In a shocking admission that's bound to make his officiating life difficult in South Africa‚ Australian referee Angus Gardner admitted to making an error by not penalising England flyhalf Owen Farrell for his illegal tackle on Springbok centre Andre Esterhuizen earlier this month.

Gardner won World Rugby's referee of the year award in an awards function in Monaco on Sunday night and was speaking on former England centre Will Greenwood's podcast.

In what became the last play of England's 12-11 win against South Africa at Twickenham on November 3‚ Farrell tackled Esterhuizen without wrapping his arms around Esterhuizen.

According to Law nine that governs dangerous play in the World Rugby Law Book‚ point 16 states a player must not charge or knock down an opponent carrying the ball without attempting to grasp that player.

In that Test‚ repeated replays showed Farrell made no attempt to grasp Esterhuizen.

“I think in hindsight now‚ having discussed it with other referees and having had some mini-camps post that game‚ a penalty should have been the outcome there and it should have been given‚” Gardner said.

“I think we need to see a wrap with both arms and in hindsight although he got pinned‚ there wasn't a big enough wrap from both arms. There was a wrap with one arm‚ but there wasn't a wrap with the other arm.”

Gardner‚ who also incurred the wrath of South African rugby supporters for his handling of South Africa's 32-19 loss against Argentina in Mendoza on August 25 during the Rugby Championship‚ said the angles available to him at Twickenham during the test influenced his decision.

Gardner also highlighted the subsequent collision between Farrell and Esterhuizen as a factor in the decision that denied the Springboks a legitimate penalty.

“The angles that I saw with the television match officials (TMO) which were the head on angles‚ showed a clear wrap of the front arm but it was the back arm that got pinned.

"I guess of the angles that I was shown in the stadium at the time‚ that seemed to me to be enough of a wrap for me to constitute a legal tackle. It was never high and what we were looking at was the tackle technique‚” Gardner said.

“The collision itself also swayed my decision because it was a big rugby collision and we see these hits in the game.”

Having not learnt his lesson‚ Farrell pulled off the same no-arms tackle on Australian lock Izack Rodda during their Cook Cup encounter at Twickenham this past Saturday.

With the incident taking place near England's tryline‚ South African referee Jaco Peyper didn't sanction Farrell nor award a penalty try.

England were leading 13-10 just before half-time and a penalty try would have given Australia a four-point lead. England went on to win the game 37-18.

Gardner said Peyper may have seen the incident in the way he saw the November 3 one but said they need to be honest about their mistakes.

“Maybe Jaco saw it in the same manner in which I saw it in the first game. We don't always get it right and we understand that there are going to be decisions that are going to heavily influence the game.

"At this level‚ the expectation is that we get it right. That's what we strive to achieve but we don't always‚” Gardner said.

“Its the best way to be honest about it. If I've made a mistake‚ I have to put my hand up and say I was wrong and hopefully‚ if I see that again‚ I'll know where I heading."