A photograph of the Arsenal star puffing on a cigarette outside a London nightclub on Wednesday emerged, leaving club chiefs furious.
The squad were given two days off and permitted a team-bonding night following their 2-0 Champions League win over Napoli on Tuesday.
Wilshere spoke exclusively to Sportsmail’s Matt Lawton just six days ago in which he admitted he was struggling with his fitness after spending a total of 17 months on the sidelines with an ankle injury.
“As for me, I’m still coming back. I still need games to reach the fitness levels I’ve achieved in the past,” he said.
“In the summer I needed to change the pins in my ankle. The old ones were rubbing against the scar tissue and making it feel uncomfortable.
“The ankle’s not worrying me now. It was bothering me last season. You’d get to a point you wouldn’t want to cross because of the pain. But it’s done now. It feels fine. I just need to get my full fitness back. My numbers aren’t quite back to where they should be.”
Wenger, who is not given to criticising his players publicly, could not hide his frustration. “I disagree completely with that behaviour,” said the Frenchman, whose side face West Bromwich Albion.
“First of all, when you are a footballer you are an example, and second, you don’t do what damages your health.
“You can damage your health at home. You can drink at home but nobody sees it, but when you do it in public, you damage your reputation as well.
“What will I say to him? I will leave that between him and me.”
The club’s hierarchy are also frustrated that they were not made aware the picture would be published, despite the fact Wilshere and his representatives knew it was about to appear in the public domain.
A spokesman for Wilshere said: ‘Jack was with friends and team-mates. One dared Jack, who does not smoke, to hold the cigarette momentarily as part of a prank.”
But one of the pictures shows Wilshere with the cigarette in his mouth and he has been given a dressing down by Wenger.
The England midfielder responded to the criticism by tweeting a picture of France legend Zinedine Zidane smoking a cigarette before insisting he himself does not smoke.
The controversy will not help Wilshere regain his Arsenal place after he was dropped for Tuesday’s win over Napoli.
Celebrity Arsenal fan Piers Morgan appeared to defend Wilshere’s actions, with a seemingly ironic post on Twitter.
Morgan wrote: ”Absolutely shocking that Jack Wilshere sneaked a crafty fag. Last thing any great midfield genius would ever do’, before linking to the picture of former France captain Zinedine Zidane puffing on a cigarette.
The post was re-tweeted hundreds of times by Twitter users, including Wilshere’s brother Tom.
Wenger is known to disapprove of his players smoking, which could spell trouble for the 21-year-old with such competition for places in midfield.
The Arsenal manager has previously reprimanded William Gallas and Marouane Chamakh for smoking in public.
“When I was a footballer, on coaches after a game you didn’t see each other because there was so much smoke,” said Wenger.
“But times have changed, they are role models now. And English society is very sensitive to smoking, much more than France, than southern countries, so it’s a bit more shocking here than somewhere else.”
Wilshere will hope to help Arsenal maintain their position at the top of the Barclays Premier League before turning his attention to England’s make-or-break World Cup qualifiers against Montenegro and Poland.
Wenger has implied the midfielder could be forced to play in an unfamiliar wide position as he looks to regain top form.
He said: “He’s an important player here. All my plans for the future at the club have been built around Jack and with Jack.
“What is Jack’s best position? Deep lying midfielder or wide.
“Playing higher up is less comfortable for him. He doesn’t like to have his back to goal. He likes to face the game because he has a burst to pass people with the ball at his feet.
“From deep he does that well, he creates openings with that little burst.
“Every good footballer says, “I want to play in the centre”. But I think for him to play on the flanks can help him find that burst.
“Will Jack be good for the two England games? Yes — even with one cigarette he will be good.”
– By DailyMail