Gibson, a New Zealand regular in recent years, will link up with the club next week after signing from Canterbury.

However, the Shoguns will not release the 19-cap international for the All Blacks' European autumn tour, effectively ending any lingering hopes of making next year's World Cup squad.

And Gibson admitted on Tuesday: "The big sacrifice I had to make was whether to go overseas now or stay with Canterbury and try to make the World Cup team."

Gibson's decision to join the Zurich Premiership's foreign legion had already put his All Blacks career in jeopardy as New Zealand prefer their Test players to be home-based.

The 27-year-old centre was named vice-captain for this year's Test against Italy but figured only as a replacement during the Tri-Nations series.

With All Blacks coach John Mitchell set to leave many of his leading men out of November's tour party, Gibson might have hoped for a chance to restake his claim.

However, his unavailability now looks like closing the door on any slim prospect he may have had of making next year's World Cup squad.

"Leaving was a really difficult decision to make having played for Canterbury for 10 years," the powerful Kiwi said.

"But I'm only 27, it's time for a new challenge and I've heard that Bristol supporters are really passionate about their rugby.

"I've watched videos of Bristol Shoguns' last three games from last season and I think they have great potential," he added.

"I had a long talk with coach Peter Thorburn a couple of months ago and was very impressed by his vision for the club."

Gibson added that he was persuaded to join Bristol by the standard of competition in the Premiership and the prospect of playing Heineken Cup rugby.

The four-times Super 12 champion has signed a two-year deal with the Shoguns.

He will arrive in England nursing an injury after breaking his nose in his farewell game for Canterbury.