Alastair Cook admits “the world changed” for England in September following Cumbrian Ben Stokes’ arrest ahead of, what has been a miserable Ashes for them, so far.

Cook will become the first Englishman to reach 150 Test caps when he tries to help Joe Root’s troubled Ashes tourists turn their series around in Perth this week, but the Essex opener says his England team-mates must wise-up off-field.

A stream of controversies has placed England’s reputation in jeopardy.

Cook concedes the bar room backdrop to England’s two defeats so far owes its genesis to Cockermouth man Stokes’ arrest outside a Bristol nightclub.

Cook, 32, knows that incident, awaiting resolution with Stokes still absent while police decide whether to charge him, has drastically altered public perception.

Two episodes, six weeks apart but played out in the same Perth bar, go a long way to proving his point.

First, Jonny Bairstow made all the wrong headlines with his misjudged “headbutt” greeting for Australia opener Cameron Bancroft; then, five days ago, Ben Duckett chose to pour a drink over all-time leading wicket-taker James Anderson’s head.

“The world obviously changed for the England cricket team in September,” said Cook.

“Those last two incidents have proven there is very little margin for error when you’ve had a beer.

“We’ve just got to smarten up, and we’ve got to do it quickly because there’s too much at stake.”

The former captain knows what it’s like to play to an unappreciative audience, having won the Ashes in 2013, only to discover most people were disengaged.

“We won an Ashes series 3-0 but the public weren’t happy,” he added.

“There was a disconnect between the players and the public, and in the last four years, we’ve made a massive effort to get that connection back.

“The last couple of months have damaged that.”

It will be a special moment when Cook wins his landmark cap tomorrow morning.

“Not many people play 150 Test matches - so to do that, and at the top of the order, I’m quite proud,” he said.

“[But] my job is to try to get England off to a good start - and on this tour, I have struggled.

“We’ve got the biggest game of our lives coming up and we’ve got to scrap unbelievably hard for the five days.

“I try my hardest all the time and I prepare as well as I can.”