BRITAIN'S longest-serving world champion believes the tenth defence of his WBO super-middleweight title in Cardiff on April 20 could be his last.

Joe Calzaghe has worn the crown for four and a half years since he won it with a points victory over Chris Eubank in Sheffield.

But with the glamour days of the 12-stone division now consigned to the history books, the 29-year-old Welshman believes the time may be right to bow to the inevitable and move up to chase a light-heavyweight belt.

"There's a possibility that I could be moving up after this fight," said the Newbridge star, who walks around at 14 stone and has always had a well-documented struggle to make the weight.

"If I can't find a big fight after this fight then I think that definitely within the next 12 months I am going to move up," he said. "It will put me in a stronger position for the bigger fights."

Calzaghe meets former IBF champion Charles Brewer at the Cardiff International Arena next, and despite a struggle to beat an ageing Herol Graham in Atlantic City in 1998, the American remains one of the best available 12-stone tests in a division struggling for names.

The best option for Calzaghe at the lower weight is a bout against the undisputed middleweight champion Bernard Hopkins, while a move up would put him in prime position for a crack at either Roy Jones or WBO champion Dariusz Michalczewski.

Calzaghe has become heartily sick of calling on Jones to fight, but admits that while a move up would cost him his coveted title it would improve his boxing.

"It is not getting any harder, but it is hard to make the weight. But I'm world champion at this weight and I get paid world champion money, so in one respect a world title shot at Michalczewski or Jones would be a step back.

"However I would like to win the world title at light-heavy. I think I'd be a better fighter at light-heavy, because it does take a lot out of me at this weight."

Calzaghe is no chaser of fame and in that respect he claims the only beef he has with missing the big all-British showdowns which preceded him is a purely financial one.

"I am frustrated that my division is not seen to be particularly strong. There are no big names. Maybe Bernard Hopkins would be a big fight, but he's not a big name. If I said oh, I'm going to fight Bernard Hopkins, the general public would say, 'Bernard who?'"

Meanwhile, Cwmbran's Gary Lockett will make the first defence of his WBO intercontinental title against Russian champion Yuri Tsarenko as Calzaghe's chief support bout.

The 25-year-old's clash will be beamed to millions of US TV viewers.