Tottenham chairman Daniel Levy has completed the signing of the midfielder at less than half the initial asking price.
Jenas had increasingly shown reluctance to play for the north-east club and recently compared the experience to being stuck inside a goldfish bowl.
The £8m cash Levy splashed on Jenas has been spent already by Newcastle. Chairman Freddy Shepherd yesterday paid Real Madrid a club record £15m to bring Michael Owen back to the Premiership.