England and Saracens number eight Billy Vunipola has been issued with a formal warning by the Rugby Football Union following his arrest in Majorca last week.
The BBC understands that Vunipola was Tasered by Spanish police and later charged with resisting arrest.
"It has been made clear to Billy that as a senior and respected player, such actions risk bringing the game as a whole into disrepute," an RFU statement said.
The warning will sit on Vunipola's disciplinary record for five years.
More to follow.