Arsenal's troubled defender Sol Campbell has returned to training after taking four days off.

Campbell was last seen publicly on Wednesday night, when he endured a torrid 45 minutes in Arsenal's defeat to West Ham.

The England centre-back was substituted at half-time and left Highbury immediately.

Arsenal boss Arsene Wenger put Campbell's departure down to "exceptional circumstances" and admitted the player was down and going through a "difficult period" in his life.

But after four days lying low, Campbell returned to Arsenal's London Colney training ground this morning.

Campbell has also received the backing of England captain David Beckham

"Sol is a strong person and a strong-minded person - and he will do what he wants and what he thinks best," said Beckham.

"He is at a great club and has a great, strong manager with him in Arsene Wenger. Sol is one of the mentally strongest people I know," he said of the 31-year-old.

Beckham expects to find out for himself that Campbell is back to his best when he and his Real Madrid team-mates face Arsenal in the Champions League this month.

"I'd love him to be playing against us, because he is one of my closest friends and because he is a great player - and you want to play against the best," added Beckham.

"People have said there have been mistakes made on the pitch. But Sol is a great player, and you don't become a bad player just because of two or three bad games."