Speaking after England's 56-run victory at Southampton, McCullum explained that while the squad remained aware of the ECB's revised code of conduct, he believed the occasion warranted a measured celebration following a successful campaign.

England's management had tightened off-field regulations earlier this year by introducing stricter behavioural expectations and a midnight curfew following a series of disciplinary issues on overseas tours. Updated guidance circulated within the squad also recommended that players avoid alcohol from the day before a match until the day after its conclusion, although the policy allowed for exceptions at the discretion of McCullum and managing director Rob Key.

After sealing the series against India and climbing to the top of the ICC men's T20I rankings, McCullum said the circumstances justified a relaxed approach.

“For a start, there's not many of our guys that actually drink, but anyone that wants a beer can have a beer, yes. The guidelines are in place. People are very aware of the guidelines. They've been sent around. The policy is designed to make sure that people are being looked after and making the right decisions,” McCullum was quoted by Cricinfo.

The former New Zealand captain stressed that the emphasis remained on responsibility rather than restriction, adding that the squad had earned the chance to enjoy its achievement.

“I trust the players completely. All the information is there. You still have to feel the warmth of success and if you are someone that likes a beer, then tonight is a great opportunity to be able to enjoy yourself - as long as it's sensible, and it's not to excess - and allow something that you've achieved over the last ten days or so sink in the way that you want it to,” he added.

McCullum also issued a light-hearted reminder that celebrations should remain out of the headlines. “But everyone's very aware of it (the guidance) and I think we'll have a quiet beer and just let this one land - just as long as no-one lands on the front page.”

The revised guidance follows a number of off-field incidents involving England players over the past year, including breaches of team protocols and late-night outings that prompted the ECB to revisit its code of conduct.

McCullum also reflected on the development of England white-ball captain Harry Brook, who has emerged as one of the team's senior leaders after learning from mistakes made earlier in his career.

“He probably didn't quite understand the standing he had within the game and English cricket, and the responsibilities that come with that stuff. Sometimes, a mistake like that can be the making of someone. He acknowledged that he's grown immensely since then, and he's got a significant future in front of him as a leader in English cricket,” he said.

Praising Brook's influence in the dressing room, McCullum described the Yorkshire batter as someone whose growth had extended beyond his on-field performances, as he said, "I consider him not just a good mate, but I feel like he's almost one of my other sons. He hasn't always got everything right and he's made mistakes off the field, but the growth that we've seen in him over the last 12 months or so has been immense."

He continued by highlighting Brook's growing stature within the England setup, saying, "He's very well respected in the dressing room as a leader, as a tactician, and obviously as a player, but he's growing at unbelievable speed and I thoroughly enjoy working with him. I feel like we're able to get the best out of each other, and I'm sure that'll continue over the time to come."

McCullum also pointed to the team's response after a difficult period that included a Test series defeat to New Zealand and Ben Stokes' retirement from international cricket. He said the players had done well to keep their attention fixed on the immediate challenge against India.

“(Winning 4-0) is immensely satisfying, so a week is a long time in sport. Things can alter quite quickly, and the key is to try to remove the emotion from things at times, and still look at the job and the task at hand. I thought the boys were brilliant at that,” the 44-year-old said.

One-off Test: Yastika Bhatia hits 91 not out as India extend lead over England to 365 runs

‘You still have to feel the warmth of success’: McCullum relaxes England's alcohol policy after India series sweep

FIFA WC: 'This team never stops believing,' says Messi after Argentina reach the semi-final

One-off Test: ‘I've never seen anything like Heather Knight before,’ says Alex Hartley for retiring England great

Andhra Pradesh CM congratulates Indian archery team for winning silver medal

Never seen a more confused Indian cricket team management, says Mohammad Kaif

‘I was receiving calls demanding Rs. 7.5 lakh to get case withdrawn’: Shashank Singh

One-off Test: India are well on top, they can bat England out of the game, says Farrant

One-off Test: I am happy and content with the decision, says Knight on international retirement

NRAI launches national shooting camp ahead of ISSF World Cup and Asian Games

Prince, Bishnoi replace injured Rana, Chakaravarthy in India's white-ball squads for ENG and ZIM series

FIFA WC: Haaland's dad claims Norway were ‘robbed' after QF loss to England

FIFA WC: ‘It’s just a football match’, Scaloni plays down Argentina-England rivalry ahead of semis

Yellamaraju, Theegala slip as bad weather halts Scottish Open third round

Aditi tied-33, Haeran Ryu storms into three-shot lead at Evian Championship

PBKS batter Shashank alleges extortion plot in assault charges, terms FIR 'tool of harassment'.

‘My happiness knows no bounds,’ says Kranti's coach on pacer's 5-fer at Lord's

'It's harsh to say Iyer's captaincy future is in jeopardy': Nayar

One-off Test: Kranti’s Lord's prophecy comes true with iconic honours board entry

'We're punished by a mistake': Swiss coach slams 'unacceptable' Embolo's red card after QF loss

'I'm not going to take the small one': How a bathroom break trophy sighting inspired Noskova's Wimbledon glory