Dylan Hartley's participation in the World Cup has been plunged into grave doubt after the England hooker was cited for an unprovoked headbutt in his club's Aviva Premiership semi-final.
Hartley thrust his head into the face of opposite number Jamie George during an off-the-ball incident that unfolded in the moments after Northampton had scored a try through Tom Wood in their 29-24 defeat by Saracens at Franklin's Gardens on Saturday.
George appeared to be unsighted at the time and the incident provoked an angry response from several Saracens players, but neither referee Greg Garner nor the television match official took action despite viewing replays.
Hartley must appear before a Rugby Football Union disciplinary panel this evening; with the entry point sanction for the offence starting at four weeks, his involvement in England 2015 is under serious threat.
"Dylan Hartley was cited following the Premiership semi-final match between Northampton Saints and Saracens for striking an opponent with his head, contrary to Law 10.4(a)," an RFU statement read.
Hartley has an appalling disciplinary record, having missed virtually an entire year of his career - 50 weeks - through suspensions incurred for a range of offences including gouging, biting and abusing a referee. If the hearing sees the 29-year-old Northampton captain found guilty, disciplinary regulations state that any ban must include matches.
The minimum sanction of four weeks would mean he misses all three warm-up games for the World Cup, starting with France's visit to Twickenham on August 15.
England head coach Stuart Lancaster would have to consider the wisdom of picking a player who would have been inactive since May in his final 31-man squad.
Further muddying the waters is whether Lancaster finally loses patience with his most capped international and opts to send the front-row into Red Rose exile.
As recently as December, Hartley was sent off for use of the elbow against Leicester, and having served the ensuing three-week ban he was then dispatched to the sin-bin for tackling on the ground in his comeback game.