Cooper sat on the bench as Gloucester faced Saracens at Vicarage Road yesterday, although he was among five visiting substitutes not used by head coach Dean Ryan.

But the International Rugby Board’s regulations committee ruled 29-year-old Cooper should not be released by Wales.

Cooper is part of Wales boss Warren Gatland’s autumn Test squad currently preparing to meet New Zealand in Cardiff next Saturday, a match which falls inside the IRB’s autumn Test window.

Under IRB regulations, Wales have first call on their players during the official three-match November international window.

Gloucester could now face an IRB sanction, despite Ryan claiming everything had been done by the book.

Cooper did not play against Canada on Friday night but he has been training with the squad and is expected to be involved against New Zealand.

Before the match, the WRU released a statement which said: “The Welsh Rugby Union can confirm that it has received confirmation from the International Rugby Board that the IRB regulation committee has ruled Wales scrum-half Gareth Cooper should remain with the WRU this weekend, and that the WRU need not release him back to his club Gloucester for the match against Saracens.

“The IRB confirmed that both the RFU (Rugby Football Union) and Gloucester have been informed of this ruling.”

Then after the Saracens match, a WRU spokesperson said: “We are seeking to establish all the facts, and once that is done we will consider all the material issues and act accordingly.”

Ryan countered: “Everybody involved in this situation knew of our decision when we took it at noon on Sunday.

“That includes Premier Rugby (umbrella organisation for the 12 Premiership clubs) and every other body who are involved, so everyone knew we were going ahead and naming Gareth on the bench for the game.

“All parties who are involved have seen that we included him on the bench and have seen what has been said, so what happens from here is for other people to decide.”

It is the latest political development in a difficult month for Gatland.

He looks certain to be without Cooper and Sale Sharks scrum-half Dwayne Peel when Wales conclude their autumn schedule against Australia on November 29.

Because that game is outside the IRB window, the players’ clubs have first call on their services, with Gloucester hosting Northampton that weekend and Sale tackling Leicester.

And preparations for the opening autumn fixture against world champions South Africa were hit by a player release row between the WRU and Wales’ four professional regions that resulted in the WRU obtaining a High Court ruling and claiming victory.

Gatland, meanwhile, should learn later today whether or not Ospreys fly-half James Hook will be available to face the All Blacks.

Hook limped off after just 18 minutes of the 34-13 success against Canada, nursing a knee tendon injury. He was due to have undergone a scan over the weekend.

Gatland names his team to meet New Zealand tomorrow.