A specialist today confirmed Phillips requires surgery and he will now miss the Ospreys' challenge for an EDF Energy Cup and Heineken Cup double and Wales’ two summer Tests against world champions South Africa.

The injury is a tough blow for Phillips, who had established himself as Wales' first-choice scrum-half during the Grand Slam and was short listed as one of the six players of the tournament.

But Wales assistant coach Rob Howley is confident Phillips has the mental toughness to return as good as new in time for the first autumn international, against the Springboks on November 8.

''Mike has been in a rich vein of form throughout the Six Nations and has proved to us all what a top-quality player he is,'' said Howley.

''Long-term injuries like this are a blow whenever they occur and it will be a test of Mike's mental toughness and motivation for him to make sure he comes back to the same standard he had reached when he picked up the injury.”

''Mike will be eager to get back on his feet and he'll work as hard as ever to get himself back to the top level and, hopefully, he will be available to us again in the autumn.”

''In the meantime we have good cover in his position with both Dwayne Peel and Gareth Cooper now likely to be in the frame.''

The loss of Phillips for the summer tour, which pitches the world champions against the Grand Slam champions, is the first significant injury blow suffered by new coach Warren Gatland since he took over.

It is thought Cardiff Blues flanker Robin Sowden-Taylor is also likely to miss the trip after injuring his shoulder in an illegal tackle by Llanelli Scarlets prop Deacon Manu last Friday.

But Martyn Williams, who came out of retirement to play such a crucial role in the Grand Slam triumph, has confirmed he will tour after Gatland gave him the option of a summer off.

Williams said: ''We just had a very casual chat where he (Gatland) asked me how I was feeling and whether I fancied going on tour.

''I said if you want to take me I will definitely go and we just left it at that really. I didn't think I would be going, but by all accounts from when I spoke to him he is keen to take me - and I'm keen to go.''

Wales are in a strong position at scrum-half with Peel, who was short of match fitness during the Six Nations, capable of slotting straight back into the side against the Springboks.

The Ospreys have experienced cover of their own as they prepare for a two-pronged assault on silverware.

Former All Black Justin Marshall is likely to reclaim his place for the Heineken Cup quarter-final against Saracens a week on Sunday and the EDF Energy Cup final against Leicester on April 12.

Phillips' international form had seen him promoted ahead of Marshall for last weekend's 30-3 EDF Energy Cup quarter-final win at the Millennium Stadium.

Ospreys head coach Lyn Jones said: ''This is very disappointing news for both Mike personally and for the Ospreys, particularly coming at a time when both his form and confidence have been high.''

Phillips suffered a tear to the anterior cruciate ligament and a grade-two tear to the medial collateral ligament.

Ospreys physio Chris Towers described the injury as ''common'' and ''unavoidable'' and is confident Phillips will make a complete recovery.

''Having seen the specialist today, the opinion is that the treatment of choice is for him is to undergo surgery to repair both ligaments in order to ensure the best functional outcome,'' said Towers.

''The injury happened when he received an impact to the outside of his right knee.”

''He wanted to stay on and continue playing, which is an indication that Mike is a pretty tough cookie, but it was clear that there was a problem and our worst fears have been confirmed.”

''The good news is there are plenty of top-flight rugby players and Premiership footballers out there who have suffered similar injuries and are back doing the business as good as ever, and there is no reason to think that Mike should be any different.''