Shields, 30, joined the Saints from Ulster in the summer of 2007. Capped twice by Ireland, he made 41 appearances in the black, green and gold and scored six tries.

The last two seasons have certainly been a successful time for the hooker, who collected winners' medals from the European Challenge Cup (by virtue of playing in the group stages), National League One and EDF Energy National Trophy, which added to his Celtic League and Celtic Cup winners' medals from his time at Ulster.

However Shields suffered a neck injury in March which has forced him to reluctantly retire on medical advice.

"Moving to Northampton was the best move I ever made, rugby wise, and I'm devastated that I have to retire," Shields said today. "The fans have been wonderful, the town has been wonderful and my family and I are very settled here.

"The coaching and medical staff have been tremendous with me through what has been a very hard time following my injury and I would like to thank them for their support.

"I'll miss playing with the boys. I've made some great life-long friends and I will really miss running out at Franklin's Gardens. In a small way I'm happy that I ended my playing days here because where else is better to play?"

However Shields will continue to be a familiar face at Franklin's Gardens, assisting in the administration of team affairs while continuing his rehabilitation from injury under the watchful eyes of the club's medical team. Furthermore Shields's wife Gemma will be launching the Northamptonshire franchise of Rugbytots, a weekly play session for children between the ages of two and seven.

"Paul is one of the biggest characters at the club and it is sad that injury has forced a premature end to his career," said Saints director of rugby Jim Mallinder. "However I'm happy that Paul and Gemma have decided to stay in the area and remain close to the club."