Ashton has not played for Wigan since 5 August

Ashton, who has been left out of the Wigan squad for their last two matches, signed a three-year contract with the Saints in March.

"Chris was anxious to commence his rugby union career with Northampton," said Wigan chairman Maurice Lindsay.

"It is pointless having a player whose mind is elsewhere."

Lindsay added: "We decided to terminate his contract with us and he will join Northampton immediately."

The 20-year-old, who has not played for Wigan since the defeat by Warrington on 5 August, was set to link up with Northampton when his Warriors deal expired in November.

606: DEBATE Have Wigan made the right decision?

That would have seen him miss the start of the rugby union season but he will now be available for the beginning of the campaign as Saints begin their bid to get back into the Guinness Premiership following last term's relegation.

The decision to let Ashton leave means Wigan are short of specialist cover at full-back, with Michael Withers having retired because of injury in June.

Winger Pat Richards has been filling the number one shirt for the Warriors in the last two weeks.

Ashton, who was a member of England's triumphant Federation Shield team last autumn, has fallen out of favour at Wigan in the wake of his defection.

"I'm looking forward to the challenge," said Ashton.

"There are plenty of differences between league and union and plenty of new skills for me to learn.

"I loved playing for Wigan and would like to thank everyone at the JJB. But it's time to move on. Northampton is a big club, and Jim Mallinder, Dorian West and Paul Grayson are excellent coaches and I'm looking forward to learning from them and the Saints players."