France and Saracens back Thomas Castaignede has announced his immediate retirement from rugby, barring selection for the World Cup.

He will continue to train with Saracens in the hope of being selected for Bernard Laporte's World Cup squad tasked with winning the trophy on home soil in September and October.

"It is time to begin contemplating a return to real life, because I've been living my dream for 14 years," the 32-year-old wrote in The Guardiantoday.

"My career in the game has brought me a lot. I left a small village in the south-west of France and ended up making my home in one of the world's great cities.

"I've met some great people, played with players I truly admire. Even though I have an engineering degree I would be capable of running a hospital with all the injuries I've had but, in spite of that, and in spite of the Achilles tendon tear that had me on crutches for a year and left me wondering if I would walk again, there have not been many bad moments."

Castaignede, who made his international debut in 1995, was arguably the world's best outhalf at the end of the 1990s before his career was hit by injuries.

He has won 52 caps, appearing more recently at fullback or centre.  He has spent seven years at English club Saracens, after playing for Castres and Toulouse, winning four French titles and a European Cup with the latter.

His "worst moment" in the game came as recently as last weekend's 50-9 hammering by Gloucester in the Premiership semi-finals.