The England & Wales Cricket Board has launched an investigation into “a breach of team protocols” after Ben Stokes and Gus Atkinson were involved in an unspecified incident in a London nightclub in the early hours of Monday.

The incident occurred in the hours after the first Test against New Zealand concluded at Lord’s, with England sealing a convincing win on the fourth day. “I’m obviously very, very happy that we’ve won this week,” Stokes said immediately after the game ended, “but I probably won’t be real happy and smiling until I get up there and share a proper beer with the boys.”

Both players have been referred to the Cricket Regulator, an independent disciplinary body with the power to impose suspensions and unlimited fines, and could be forced to miss the second Test that starts at the Oval on 17 June.

“The ECB is currently investigating a breach of team protocols following the conclusion of the first men’s Test against New Zealand,” a statement read. “Ben Stokes and Gus Atkinson were present at a nightclub in the early hours of Monday morning when an incident took place. We are currently seeking further information, and an announcement regarding the squad for the second Test will be made in due course. The Cricket Regulator has been informed and we will provide a further update when possible.”

The development, particularly given it involves the Test captain, will be a humiliating blow to a set-up attempting to move on from the various missteps that characterised their winter. Harry Brook, England’s white-ball captain, was involved in an altercation with a bouncer outside a nightclub in Wellington, New Zealand, on the night before an ODI last November and then compounded that embarrassment by twice lying about it to the media. Both he and Jacob Bethell, who was also present, were reprimanded by the Cricket Regulator.

Then the Test side went on a mini-break in the Australian coastal resort of Noosa between the first two Ashes Tests, during which videos of inebriated players circulated on social media. “If it’s true that it became a stag do and people are out drinking all the time excessively, that’s not acceptable,” said Rob Key, England’s managing director of men’s cricket. “I don’t agree with a drinking culture. I don’t like a drinking culture.” A review into that incident led to the introduction of a midnight curfew for players while they are on tour.

Team management have attempted to brand this summer as a reset both on the pitch – as a reaction to the 4-1 defeat in the Ashes – and off it, with the men’s coach Brendon McCullum promising to “use a firm grip” to deal with a perceived drinking culture within the group.

“From a cultural point of view and a discipline point of view, we need to make sure we’re operating in the manner that we want to and what’s expected of us,” McCullum said, in the build-up to the first Test against New Zealand. “Playing professional sport is a great career and it’s great fun, but ultimately you’re representing your country and you’ve got some responsibilities and obligations to carry yourself in the right way. So [my job] is to ensure that remains strong and continues to improve.”