The 29-year-old dislocated his right shoulder in Cardiff Blues’ Magners League victory over Newport Gwent Dragons last night and was immediately taken to hospital for an X-ray.

A further scan this morning revealed the need for reconstructive surgery on the joint, and with the Lions heading for Africa in just 17 days’ time, Shanklin’s hopes of facing the Springboks are over.

Blues chief executive Robert Norster said: “I'm sure I can speak on behalf our the entire Blues family, indeed the entirety of Wales when I offer our sympathies to Tom following his devastating shoulder injury suffered last night that will prevent him travelling with the Lions to South Africa this summer.

“Tom and all our other Lions heading south have given their very best for the Blues and their country this year and such injuries hardly seem fitting or fair.

“Suffice to say Tom picked up the injury whilst giving his all for our team and we are all feeling for him at this difficult time of disappointment and frustration.”

The powerful midfielder walked gingerly off the Arms Park pitch with his right arm wrapped in his shirt late on in last night's 26-12 victory.

Shanklin, who had earlier scored a try, appeared to pop the joint as he crashed to the floor in contact.

He had been pencilled in for a possible place in the Lions Test side, when his physical presence would have been a potentially vital asset against the muscular Springboks.

His absence could now open the door for international team-mate Gavin Henson, although his chances are hampered by a lack of recent action.

Shanklin's heartbreak presents another major poser for Lions head coach Ian McGeechan, who has had his fair share of troubles since announcing a 37-man tour squad last month.

Munster and Ireland scrum-half Tomas O'Leary was ruled out of the 10-match trip just three days after being selected for it due to a broken ankle suffered on Magners League duty.

McGeechan and his coaching staff have yet to choose a replacement, although a decision is likely after this weekend's Guinness Premiership play-offs, with England's Danny Care among the leading candidates.

The first tour match against a Highveld XV in Rustenburg is on May 30.