Rugby:Wales centre Tom Shanklin has announced his retirement from rugby due to a knee injury. The 31-year-old Cardiff Blues player underwent surgery earlier this year in an attempt to cure the problem.

But Shanklin, who won 70 Wales caps and toured New Zealand with the 2005 British and Irish Lions, has followed medical advice and will end his playing career.

He said: "My knee isn't too bad - it's okay to walk and cycle and to do everyday things. But with regards to playing rugby - accelerating, changing direction, weightlifting - it's not too good.

"I had an operation in January to see if we could fix the problem, and it hasn't worked. It's bone on bone on my knee which has restricted me from doing a lot of things, and I am going to have to retire from the game.

"The advice from Rhys Williams, the surgeon, was to retire. Rhys knows the inside of my knee pretty well, having done three or four operations on it.

"It was down to me to decide if I could continue or not, but I can't go on as it's too sore. It's a pretty black and white situation. I cannot fully function with it, and I need to start taking account of my body and start listening to it."

Shanklin's 2005 Lions tour was ended abruptly because of knee trouble, while a shoulder injury meant he had to withdraw from the 2009 Lions squad before departure after being selected for the three-Test South Africa trip.

But former Saracens star Shanklin, whose father Jim also played for Wales, still enjoyed a highly-successful international career and was part of Wales' Six Nations Grand Slam successes in 2005 and 2008. He scored 20 Test tries.