Trundle was a fans' favourite at the Liberty Stadium

The 30-year-old striker agreed personal terms on a three-year deal with the Robins last week after handing a transfer request at Liberty Stadium.

He played for his new club on Saturday in a friendly with Yeovil after being given special dispensation by the FA of Wales and Swansea.

The deal was finalised between both clubs on Monday, with Swansea receiving their record transfer fee for a player.

"I want the Swansea fans to know how hard this decision was, I don't want there to be any bitterness after all we've been through together," said Trundle.

606: DEBATE Trundle's record is very good no doubt about that AG

"In the end I decided I had to go because I didn't want to take the risk of not getting another opportunity to play in the Championship, which is somewhere I want to prove myself."

City manager Gary Johnson was in the market for a new striker after Steve Brooker suffered a setback to his recovery from knee injury.

The Swans turned down a �750,000 bid from Sheffield Wednesday for Trundle in 2005.

But Swansea chairman Huw Jenkins said this time there was little point in trying to force the player to stay.

"We've tried everything possible to keep Lee and spoke about a wage increase, but it was never about money," he told the Swansea website.

"What we couldn't offer was Championship football. It's a sad day for the club, he's been fantastic for us."

Trundle has been a fantastic servant to Swansea and he knows how much we think of him Swansea manager Roberto Martinez

Jenkins' feelings were reflected by Swansea manager Roberto Martinez, who said last week that he would "never try to sell" Trundle.

"Trundle has been a fantastic servant to Swansea and he knows how much we think of him," said Martinez.

"The timing is not ideal, but we are already looking to bring somebody in.

"We need to be strong and look forward. I have huge confidence in the players in my squad, they will relish the extra responsibility."

Despite his prolific scoring exploits since joining from Wrexham in 2003, Trundle would have faced stiff competition for his place at Swansea next season following the arrival of strikers Jason Scotland, Darryl Duffy and Guillem Bauza.

The Liverpudlian scored 86 goals in 178 games in all competitions for the Swans, topping the 20-goal mark in all his four seasons at the club.

He was given his first shot at professional football by Wrexham after signing from League of Wales side Rhyl in 2001.