Wigan chairman Ian Lenegan said Hock had "let down" Warriors and had "no intention" of playing for them again.
Hock's career to date
- Born in Wigan
- Scores twice on Wigan debut, named Super League's young player of the year
- Named in Great Britain's Tri-Nations touring squad and makes international debut
- Plays three games for England at World Cup, handed five-game ban for grabbing a referee in a defeat by Huddersfield Giants
- Suspended for two years after testing positive for cocaine
- Returns from drugs ban, gets five-match suspension for gouging incident at Warrington, extends Wigan stay to 2015
- Named in Super League's Dream Team, move to Parramatta Eels falls through
- Undergoes shoulder surgery, then moves to Widnes Vikings on loan
The deal is another sizeable transfer coup for Widnes, who finished bottom of Super League last year.
Half-back Kevin Brown
could make his Vikings debut in the season opener at London Broncos on 3 February after his move from Huddersfield Giants last summer, providing he recovers fully from ankle surgery.
And Widnes will pay a "significant, ongoing but undisclosed" fee for Hock, who could extend his stay with the Vikings beyond the end of the campaign.
Wigan-born Hock told
BBC Radio Merseyside:
"I played with [Widnes coach] Denis Betts and I know about 12 of the lads here that I've played with before.
"Denis coached me as well at Wigan so I know him very well and that had a part in it.
"I've got a lot of good friends here. It will be a good place for me to come and have good lads around me."
On the signing of Hock, Betts said: "It's a great statement of intent from the club. He's a current international and one of the best back-rowers in the world.
"It (the deal) has come about after a lot of hard work and a lot of understanding on Wigan's part. We've got to say thanks to them for what they've been willing to do with Gareth. The situation has sorted itself out and we've managed to get a high quality player."
“He informed Wigan Warriors that he would not be continuing his career at the club, expected the club to sack him and insisted upon a move elsewhere”
"Following his demands for more money in mid-season, insistence at short notice in October on a move to Australia and discussions instigated by the player in December around his request to move to another Super League club, Gareth Hock refused completely after Christmas to return to rehabilitation and pre-season training at Wigan," the statement read.
"He informed Wigan Warriors that he would not be continuing his career at the club, expected the club to sack him and insisted upon a move elsewhere."
"We have gone to unique lengths to help him get his life back on track after his ban two years ago, including increasing his contract voluntarily on two separate occasions to help him financially against a backdrop of his threats to leave," he said.
"A line has to be drawn at some stage and whilst with immense regret at losing a player of Gareth's quality, who I believe is still a Wiganer at heart, we have concluded that that time is now for the good of the Wigan squad, the coaching staff and for the Wigan fans.
"Since I and Wigan are not prepared to allow Gareth to play for one of our major competitors, we have decided to retain his registration and to allow him to move on loan to Widnes, with whom we have an excellent relationship.
"He is not allowed to play against Wigan in any competitions."
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