The 32-year-old brings to an end a nine-year association with the Magpies, having signed for the club in 2014 from Nottingham Forest and spending an initial year on loan at the City Ground.

He made 100 appearances for the club during his time at St. James' Park, including 34 appearances as United won the Championship title in the 2016/17 campaign to ensure an immediate return to the Premier League.

Everyone at St. James' Park thanks Karl for his service and wishes him well for the future.