AMERICAN president Barack Obama's half brother was REFUSED a visa to enter the UK after being accused of an attempted sex attack on a young girl in Berkshire.

The News of the World can reveal that Kenya-based Samson Obama tried to get into Britain on his way to Washington for his family's big day, the historic inauguration in January.

But eagle-eyed immigration officials at East Midlands Airport, using the latest biometric tests, discovered he was linked to an incident here last November. The hi-tech database revealed that Samson -who manages a mobile phone shop just outside Nairobi-was the same man arrested by British police after he approached a group of young girls, including a 13 year-old, and allegedly tried to sexually assault one of them.

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He then followed them into a cafe where he became aggressive and was asked to leave by the owner. That's when police were called and Samson was arrested.

He supplied officers with his mother's address in Bracknell but gave them a false ID, claiming to be Henry Aloo, a genuine asylum seeker.

Mum Kezia, 67, has lived in Bracknell for six years. She married the US president's father Barack Obama Snr in Kenya when she was a teenager.

Following Samson's arrest he was fingerprinted but not charged, then left the country. However, all his details were stored on the Home Office's new database of prints and biometric details. And that's what finally pinpointed Samson's link to the world's most powerful leader-as he tried to slip back into Britain to visit relatives en route to the swearing-in ceremony.

The White House was informed and a Home Office source told the News of the World: "This was obviously an extremely sensitive issue when it was flashed up by the database.

"But the system is designed to flag up people who have come to the attention of the police in the UK and are then trying to return."

It is thought that Samson-one of the President's 11 half brothers and sisters by his father who had four partners-managed to travel on to Washington by boarding a connecting flight to the US from East Midlands.

He was able to do so despite not having a UK visa because he remained in transit and never left the airport. A stewardess from nearby Nottingham told her local newspaper how she met him on his flight to America. Dawn Stewart, of Sherwood, described how Samson told her his nickname was Abo and said he was on his way to the US capital for the presidential swearing-in.

She recalled: "I asked him how he feels being the brother of the next president and he said, 'I can't tell you the depth of excitement we feel.'

"I asked what Barack was like as a teenager and he said he was always charismatic and calm."

The flight attendant said Samson claimed he had never travelled before and proudly showed her a headed letter from his half-brother requesting his three-week visa to the USA.

Last night a Home Office spokesman confirmed Samson Obama was refused a visa after immigration officers noticed one of the documents he supplied with his visa application was false. That led to further inquiries.

A UK Border Agency spokesman said: "We consider all visa applications based on their merits. We will oppose the entry of individuals to the UK where we believe their presence is not conducive to the public good.

"The UK's border controls are among the toughest in the world. All visa applicants are fingerprinted and checked against watchlists. Using this hi-tech system we have detected more than 5,600 attempts to use false identities since December 2007.

"Our officers in 135 countries are working with law enforcement agencies and airlines to clamp down on forged passports and visas."