Everitt has been a prolific goal-kicker for the Exiles

The 30-year-old is the Exiles' all-time record points-scorer with 1,725 from 164 appearances for the club.

Everitt, who previously had spells with Munster and Leinster, won the Powergen Cup final with Irish in 2002.

But the Irishman has found himself largely restricted to the bench this season, with 20-year-old Shane Geraghty establishing himself as first choice.

Everitt said: "I see this an opportunity to develop my game under a head coach like Paul Grayson, who I have a lot of respect for having played against him many times.

"This was a difficult decision for me having spent so many years with London Irish.

"But having come to Franklin's Gardens as an opposition player, I was always aware of the great sense of loyalty and camaraderie among the supporters, a similarity that is shared with the club I am coming from and at Munster.

Barry is a proven performer over a number of years Northampton head coach Paul Grayson

"Northampton are a club that is steeped in history, are past Heineken Cup winners, have been a major force in Europe for many years and have the best facilities I have seen in the Premiership.

"This is quite a commitment for me as it will probably be my last long-term contract. I look forward to the challenge ahead and being part of something special as Saints move forward."

Saints coach Grayson insisted there was more to Everitt's game than his prolific goal-kicking.

"Barry is a proven performer over a number of years and has great experience in the Premiership," said Grayson.

"His kicking game obviously stands out as exceptional, but he is a very capable footballer and distributor and there is a lot more he has to offer. I am looking forward to working with him to express his full range of talents."