England's Graeme Swann sent home with bad back

England spinner Graeme Swann is returning home from Australia because of a lower back strain but should be fit for the World Cup, team coach Andy Flower said on Tuesday.

Swann, who played an instrumental role in England's first Ashes series victory in Australia for 24 years, was already suffering from a knee injury he suffered while batting in the second one-dayer against Australia.

"Graeme Swann will be taking the earliest flight home," Flower told reporters in Adelaide on Tuesday.

"He's unfortunately got a strain in his lower back and that, allied with his knee problem, means that it is best for him to go home and get ready for the World Cup now.

"Of course it is a big blow, he's an important part of our side, he's a world class performer and he's full of confidence obviously after the Ashes. But these things happen. We are coming towards the end of a long, hard tour and certainly the physical challenges are starting to take their toll," said Flower.