An incident at a nightclub involving England cricket captain Ben Stokes, pace bowler Gus Atkinson and a Saracens academy rugby union player is being investigated by the England and Wales Cricket Board and the Prem Rugby club.
An ECB statement said the England pair were involved in a “breach of team protocols” in the early hours of Monday morning, after the conclusion of their win over New Zealand at Lord’s on Sunday.
Saracens said they were aware of an incident and were “currently establishing the full facts”.
The identity of the academy player allegedly involved has not been made public.
It is the latest controversy to hit the England team following an Ashes tour dogged with allegations of a drinking culture.
Before the Ashes, white-ball captain Harry Brook was punched by a nightclub bouncer in Wellington on the eve of a one-day international against New Zealand.
As a result, England imposed a midnight curfew on all players and staff.
It is understood the curfew was still in place despite the first Test being over, and the investigation relates to more than a breach of the curfew.
“The ECB is currently investigating a breach of team protocols following the conclusion of the first men’s Test against New Zealand,” said the statement.
“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.”
A Saracens statement added: “We are aware of an incident involving an academy player connected to Saracens on Sunday evening.
“The club is currently establishing the full facts and is in contact with the relevant authorities and individuals involved. Once this process is complete, the matter will be reviewed and addressed appropriately.”
The Sarries senior side were beaten 32-13 by Exeter in their final game of the Prem season on Saturday.