'I had nothing to prove and nothing to get my motivation levels up' - Dan Carter retires from rugby

Dan Carter has announced his retirement from professional rugby (David Davies/PA)

Former New Zealand fly-half Dan Carter has announced his retirement from professional rugby union.

The 38-year-old won two World Cups during a 12-year spell with the All Blacks and bowed out of the international scene with a man-of-the-match display against Australia in the 2015 World Cup final.