The 29-year-old informed the club that he had enjoyed his 10-year spell with the club, in which time he managed to score 104 tries in 191 games for the club.
"I have some great memories but have received medical advice that I will not recover enough to play Premiership rugby again," Hanley told the clubs official website.
Hanley managed to score a try on his only England appearance against Wales in the 1999 Five Nations Championship.



