* Marial to compete in marathon
* Lost 28 family members in Sudan civil war
By Emma Batha
LONDON, Aug 3 (Reuters) - South Sudan marathon runner Guor Marial will officially compete under the Olympic flag at the London 2012 Games but deep down he will represent his new nation and its long-suffering refugees, he told Reuters.
Marial, 28, who has lived in the United States since he was 16 having fled Sudan during the long civil war, could not join the U.S. team as he does not have citizenship.
South Sudan, the world's newest country which was recognised only last year, has not yet established a national Olympic Committee and so was not able to send a team to the Games.
Olympic chiefs had suggested Marial run for Sudan but he refused, saying it would be a betrayal of his country, his family and all those who died in the war that lasted decades until a peace deal was signed in 2005.
Marial lost 28 family members during the conflict and was kidnapped twice.
"I will be wearing the Olympic uniform, but inside I will be holding the South Sudan flag in my heart, and the people of South Sudan and the refugees," he said in a telephone interview before he flew to London.
"These are the people I will be representing at the Olympics."
Marial, who arrived in England on Friday, only learnt a fortnight ago that he could compete as an independent athlete, one of four at this year's Olympics.
"I'm very excited and very happy that South Sudan got independence and within one year has got to where it has. And I'm very grateful that the name of South Sudan is coming to the Olympics," he added over the phone.
"It's great to see a lot of people out here, being moved by my story, my case. I love the support and I'm sure I'm going to get a lot of support here," said Marial on arrival at London's Heathrow Airport on Friday.
Marial achieved the Olympic qualification time in October last year and improved his personal best in San Diego, California last month, finishing in two hours 12 minutes 55 seconds.
The world record is over nine minutes faster so Marial is a long shot for a medal, he is targeting a top 15-20 finish in the Aug. 12 marathon, but the fact he is even here is his biggest achievement.
Marial was born at the start of the war, which claimed almost all his siblings. The second time he was kidnapped he was forced to work for a year as an unpaid servant for a Sudanese soldier's family.
He fled Sudan at 14 following a night-time attack by Sudanese soldiers on his aunt and uncle's home in Khartoum where he was staying. Marial was knocked unconscious when a soldier smashed his jaw with a rifle.
He initially fled to Egypt and was then accepted as a refugee by the U.S. where his talent for running was spotted by his teachers. He is a chemistry graduate and works with people with mental disabilities when not training.
Marial, who now lives in Flagstaff, Arizona, has not seen his parents since 1993. He said they live in a remote village in South Sudan with no electricity or telephone.
He hopes someone will be able to take them to a nearby town so they can watch him compete on television.
South Sudan gained independence last July after the peace deal seven years ago ended the war between the mostly Christian south and Arab north.
Tensions remain high following clashes in contested borderlands and rows over oil payments. Sudan and South Sudan came close to all-out war in April, the worst violence since South Sudan seceded and declared its independence.
"South Sudan may not be able to raise the flag at the Olympics, but I consider myself as symbolic of the flag of South Sudan being raised in the Olympics," said Marial.
Marial is not the only refugee from Sudan to be competing in the Games. Chicago Bulls player Luol Deng, who grew up in London after fleeing the war-torn African nation, has been playing for Britain's basketball team.
Lopez Lomong, who has U.S. citizenship, is competing in the men's 5000 metres.
Marial joins 400 metres runner Liemarvin Bonevacia, judoka Reginald de Windt and sailor Philipine van Aanholt, all from the former Netherlands Antilles, to compete under the Olympic flag.