Updated

By Adrian Croft

CAMP BASTION, Afghanistan (Reuters) - British Prime Minister David Cameron brought troops in Afghanistan a message from "the most important person in England" on Friday -- England coach Fabio Capello who is leading the team into the World Cup.

Cameron, swept by a sandstorm as he addressed hundreds of British troops on a dusty parade ground at Camp Bastion in southern Afghanistan, read out a morale-boosting message from Capello, the Italian who England fans have pinned their hopes on in the World Cup which begins in South Africa on Friday.

"While the players receive incredible support from the country, as we are about to kick off in the World Cup, it's important you know how much all your efforts mean to all the players and staff with the England team," Capello said.

"Your brave service to your country means so much to the players and we all have complete respect for the incredible sacrifices that you and your families have made."

England begin their World Cup challenge against the United States in their opening Group C fixture on Saturday.

"While we will be doing all we can to achieve success in South Africa for the whole country, we want you to know that we believe that you are the real heroes," Capello's message said.

"I think Fabio is absolutely right," Cameron, who was on his first trip to Afghanistan since becoming prime minister last month, told the troops.

England star David Beckham visited British troops in Afghanistan just a few weeks ago to help boost the morale of the troops, who have suffered heavy losses in fierce fighting with Taliban insurgents.

Cameron admitted that his enthusiasm for the England team had not gone down well with Scottish troops serving in Afghanistan. Scotland, traditional rivals of England on the soccer pitch, failed to qualify for the World Cup.

"Last night I was talking to some of the Scots Guards and of course I was saying 'Come on guys, you've got to be cheering on England.' I cut a deal with them. I said 'If it ends up as England-Argentina you've got to cheer for England'," he said.

(Editing by Michael Holden)