* Abdul Haroun nearly made it to Britain on foot

* Faces charge of blocking railway under 19th century law

* Will claim protection under refugee convention

* Eurotunnel wants prosecution to deter others (Adds details, quotes)

By Estelle Shirbon

CANTERBURY, England, Aug 24 (Reuters) - A Sudanese migrant who walked 50 km (31 miles) from France to Britain through the Channel Tunnel as trains rushed past, only to be caught near the British exit, appeared in court on Monday and said he was not guilty of an obscure 19th-century offence.

Abdul Haroun, 40, made global headlines after his dangerous crossing on Aug. 4 highlighted the desperation of thousands of migrants camping in squalor near the French end of the tunnel at Calais as they seek clandestine ways to reach Britain.

Part of a wider European migration crisis, the chaos in Calais has disrupted traffic, prompted a security crackdown by French and British police, and divided Britain between those who want tougher measures to keep migrants out and those who call for greater solidarity with people fleeing war or oppression.

While most migrants in Calais attempt to hide on lorries or trains bound for Britain, Haroun was the first to make it on foot almost to the tunnel exit at Folkestone in England.

Having got past security fences and avoided detection by closed-circuit television cameras and search teams, he spent almost 12 hours walking along the track in the darkness as trains sped past him at speeds of up to 160 kmh (100 mph).

He is charged with "obstructing an engine or a carriage using a railway" under the Malicious Damage Act of 1861.

His case has stirred debate, with tunnel operator Eurotunnel saying it hoped the full force of the law would be used to deter others from following Haroun's example, while refugee rights campaigners say he should not be prosecuted at all.

Little is known about Haroun. His lawyer, Nicholas Jones, told the court his first language was Zaghawa, suggesting that he may be from Darfur, a region ravaged by more than a decade of conflict between Sudanese government forces and rebel groups.

"SO NEARLY MADE IT"

Short-haired and wearing a light grey t-shirt, Haroun appeared by video-link from Elmley Prison for a brief hearing at Canterbury Crown Court in Kent, southeast of London.

He confirmed his name and, after the indictment was read out and translated into Arabic for him, he responded through a court interpreter that he was not guilty.

Jones said Haroun's defence would be that he caused no obstruction and that he is protected by Article 31 of a U.N. convention under which refugees cannot be prosecuted for using irregular means to enter a country of sanctuary.

Some lawyers and refugee rights campaigners accuse the authorities of treating Haroun harshly to send others a message.

"The prosecution of Mr Abdul Rahman Haroun for an obscure 19th century railways offence is inappropriate and wrong," wrote lawyer Colin Yeo, a prominent asylum specialist, on his blog.

A spokeswoman for the Home Office, or interior ministry, said the decision to charge had been made by the police and offered no further comment. The police declined to comment.

At the end of the hearing, Judge Adele Williams set a trial date of Jan. 4, 2016, and remanded Haroun in custody.

When he heard that he was to remain in prison, Haroun appeared to become agitated, raising both arms and beginning to speak in Arabic, but the judge cut him short and the video-conference link was disconnected.

It is not clear whether Haroun's prosecution would hinder an application for asylum in Britain. The Home Office spokeswoman said cases were examined individually on their merits.

According to the latest official figures, 79 percent of the 1,603 Sudanese applicants for asylum in Britain in the 12 months to March were granted refugee status at the first attempt.

The maximum penalty for the charge that Haroun faces is two years in prison. Campaign groups said applications for asylum could take months or years due to the slow bureaucratic process.

"This is an unusual case because of his immense courage in doing the walk, and because he so nearly made it," said Sue Powell of Kent Refugee Help, a small non-governmental group. (Editing by Mark Heinrich)