Wasps boss David Young is "bitterly disappointed" that potential England forward Billy Vunipola will leave them and join Saracens next season.
Saracens announced a double swoop on Monday afternoon, recruiting 20-year-old Vunipola and Samoa prop James Johnston from Premiership champions Harlequins.
Vunipola will link up with his brother, England prop Mako, in north London next term but Wasps have been left reeling by his decision, which comes less than a week after England head coach Stuart Lancaster confirmed he would train with the national squad in Leeds later this month ahead of the RBS 6 Nations.
"We are clearly hugely disappointed," Wasps rugby director Young said.
"Billy is a player that the club identified some time ago as one with huge potential, and he has been developed by Wasps - despite a period when he struggled with illness and injury - into one of the brightest young talents in English rugby.
"During our contract talks, the player had been adamant that he did not want to leave the club, but we know he was under pressure for family reasons to go and join his brother at Saracens.
"We did everything in our power to keep Billy. We offered him the contract he asked for.
"He is playing regularly and he has already got international recognition, so we didn't see any reason for him to leave.
"Although we had heard the whispers about him going to Saracens, we were only officially informed yesterday afternoon that Billy was leaving and he had previously signed for them.
"Although we are bitterly disappointed right now, it is only fair for me to say that I believe that Billy will become a top-quality international player for years to come and we wish him the best with his career.
"There is a long way to go in the season, and I am sure he will give his all for Wasps in the coming months."
The summer departure of 26-year-old Johnston from the Twickenham Stoop will leave Quins with a considerable front-row void to fill.
"We are very disappointed to lose a player of James' ability," Quins rugby director Conor O'Shea said.
"He has developed greatly since he joined us four years ago, and I am sure he is destined for great things in the game.
"Unfortunately, given the constraints of the salary cap, we were unable to meet his financial expectations so he has decided to move on at the end of the current season.
"But I know he will give his all to go out on a high from the club that has become his extended family and means a great deal to him.
"We are in the fortunate position of having two of the most exciting young tighthead props in the country coming through our system in Will Collier and Kyle Sinckler, and we are confident that we will be able to recruit another experienced front-row forward to complement them shortly."
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