England hooker Dylan Hartley

London (AFP) - Former England captain Dylan Hartley announced his retirement from rugby on Thursday after failing to recover from a long-standing knee injury.

The 33-year-old, England’s second-most capped player with 97 Test appearances, skippered his country to the 2016 Six Nations Grand Slam.

Hartley, who had a poor disciplinary record, was a surprise choice for many when England coach Eddie Jones appointed him captain after the disastrous first-round exit at the 2015 World Cup.

Jones paid a handsome tribute to the New Zealand-born Northampton star, who also led England to the 2017 Six Nations title and who captained his country on 30 occasions.

“Dylan has had a significant international career playing for his country, having played 97 Tests, and was a tough, enduring character for us,” said Jones.

“He was a foundation captain and we owe him a lot for his contribution to the making of this team.

“We will be forever indebted to him for his dedication and commitment to the team and his love of English rugby.”

Hartley, who made 251 appearances for Northampton and captained them to the Premiership title in 2014, admitted it had been a tough year battling with the knee injury.

“The last few months have been difficult for me both mentally and physically as I’ve come to terms with the fact that I am no longer able to compete,” said Hartley, who has not played since December.

“My career wasn’t perfect, but I wouldn’t have had it any other way.

“I’m privileged to have experienced some amazing highs while there have also been some personal lows, all of which are powerful experiences that will stay with me forever.

“The final chapter of my career was supposed to go a different way, but that is the nature of professional sport.”