Wales have dropped Andy Powell from the national squad following his drink-drive charge after an alleged golf buggy incident.
The back-row was arrested with another man at 0540 GMT on Sunday at services off junction 33 of the M4 near the team hotel in the Vale of Glamorgan.
That was hours after he played in the dramatic 31-24 win over Scotland.
Wales team manager Alan Phillips said: "This kind of behaviour cannot be tolerated."
Phillips revealed Powell has apologised to Wales' management and was also asked to apologise to the hotel management before being asked to leave the squad.
A Welsh Rugby Union statement read: "After discussions with the player himself, it has been decided by management that he should be suspended from the squad for behaviour contrary to the squad's code of conduct."
Phillips added: "We take matters of player conduct extremely seriously and have been happy with the professionalism and discipline of this squad in general terms," said Phillips.
"Andy knows he has misbehaved and is apologetic, but he also knows that he must take responsibility for his own actions and accept the repercussions.
"This kind of behaviour cannot be tolerated in a professional, elite sporting environment and we have acted quickly and incisively in order to leave no ambiguity over the dim view we take of this situation.
"The player has made his private apologies to the Welsh management team as well as apologising in a public statement and we have also asked him to apologise to the Vale Resort Hotel, before asking him to leave the squad.
"We will now leave the South Wales Police service to conclude the matter and we will be making no further public statements at this time."
Cardiff Blues chief executive Robert Norster said: "The news of what appears to be a bizarre but serious lack of judgement by one of our players whilst on national duty is of real concern.
"It seems, albeit from a distance, to have been a prank that has somehow gone dreadfully wrong with potentially very serious implications.
"Consequently, we fully accept and respect the WRU's understandable and prompt action to address the issue. Naturally, as this is an ongoing police matter, we will also not be commenting further at this time".
On Sunday's Scrum V, ex-Wales captains Phil Bennett, Robert Jones and Mike Hall suggested this may spell the end of his Wales career.
"I think he [Powell] has gone," former British and Irish Lions three-quarter Hall told BBC Wales' Scrum V rugby programme.
"I don't see him featuring against France at all and I don't think this management team will put up with it.
"It's without question [enough reason to be dropped from the squad], an extremely stupid thing to do.
"He's a high profile public figure and I think [Wales coach] Warren Gatland will come down on him like a ton of bricks."
Powell faced the Wales team management on Monday.
The player was also bailed on Monday morning and will appear in court next month charged with drink driving.
Brecon-born Powell, 28, has won 14 caps and toured with the Lions squad to South Africa last summer after a breakthrough season for Wales.
The Cardiff Blues man has been a favourite of Gatland's and last season he displaced Wales captain Ryan Jones from his favoured number eight position before being chosen ahead of his national skipper for the Lions tour.
Jonathan Thomas is probably a better bet because he's more of a natural number six, Powell is a number eight
Robert Jones
But this season Jones has regained his favoured eight jersey meaning that Powell has been moved to the blind-side flank.
His position may have been under threat before the buggy incident, with many fans and pundits calling for Jonathan Thomas to take the number six jersey.
Former Scotland scrum-half Bryan Redpath told Scrum V that playing Powell out of position was having a knock-on effect on open-side flanker Martyn Williams' effectiveness, and Bennett and Jones agreed that changes should be made.
"Powell was struggling to stay in the team on form anyway," former Wales and Lions fly-half Bennett told Scrum V.
"[Against Scotland] we were devastated by their back row.
"I'd be looking to move Jonathan Thomas back to six to give us some height."
Former Wales and Lions scrum-half Jones added: "Our combination in the back row is not right.
"What is the job of a six? He's there to hit rucks, to do all the donkey work and to carry tightly and effectively, and that balance isn't quite right.
"Jonathan Thomas is probably a better bet because he's more of a natural number six, Powell is a number eight."
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