England flanker Lewis Ludlam will leave Premiership leaders Northampton Saints at the end of the season.

Ludlam, who has made 121 senior appearances for Northampton, turned down the offer of a new contract to remain with Saints beyond the summer.

"I know he has been torn," said Saints director of rugby Phil Dowson.

"He has made a difficult decision and we have to accept and respect that - but it doesn't make it any less disappointing to see him move on, after we offered a new contract and tried to keep him at Saints."

Dowson said Ludlam, a player that came through the club's academy, is the "epitome" of what Saints try to do with players.

"He came in as a youngster through the academy system, got straight into work training with the first team, and has transitioned into a key player for us as well as being the captain of the club.

"He's done an exceptional job leading the group, driving the energy and standards here," Dowson added.

While it is not known where Ludlam will play next season, a potential move to Toulon would see him overlooked for England selection as the Rugby Football Union (RFU) does not allow players based abroad to be selected for the national team.

In January, it was announced fellow England international Owen Farrell would be leaving Saracens for Racing 92 in France at the end of the season.

"This has been an extremely tough decision for me," Ludlam told the Saints website.

"I believe I've given everything physically and emotionally to this club and I hope our fans have seen how much it has meant to me to represent Northampton in the way I play the game."

Confirmation of Ludlam's departure comes during a two-month break in the Premiership season to accommodate the Six Nations Championship.

Ludlam was overlooked for the tournament, having only recently returned from a two-month injury absence.

Ludlam loss 'unquestionably a blow'

Analysis - BBC Radio Northampton's Graham McKechnie

Lewis Ludlam has been a massive part of Saints on and off the pitch for a number of seasons. His commitment to the cause, as well as the fact he's home-grown, has made him hugely popular with supporters.

Not only has Ludlam been an outstanding player for Saints, he's also a natural leader of the group and has been since his days in the academy.

His mental toughness matches his physicality - he's absolutely made the most of his natural talents. So to lose a player of his stature - particularly one who's come through the academy - is unquestionably a blow.

The lack of opportunity with England seems to have partly prompted the move but, from a Saints perspective, the arrival of Tom Pearson and the emergence of Henry Pollock at least suggests the cover is there in the back row.