Nils Mordt will leave London Irish for Northampton (Getty Images)

BBC Radio Berkshire understand that Mordt, who represented England Saxons and Sevens last season, will join Northampton Saints.

He has played 61 senior games for Irish since graduating from the club Academy.

Mordt said: "I've reached the stage where I need to have a regular starting place in a Premiership team."

He added: "I've had six great years at London Irish. I've worked with great coaches, played with world class players and enjoyed the encouragement of supporters that make the club the exceptional place that it is.

"London Irish and its supporters will always be special for me and I wish the club and all involved with it the very best for the future."

Brian Smith, London Irish's director of rugby said: "We can understand Nils' decision to leave at the end of the season although we're sorry to see him go."