Dozens of Islamic extremists have returned to Britain from terror training camps in Somalia, the British security services believe.

Intelligence analysts are worried that they may attempt to launch attacks in this country or use the kudos from having trained and fought in Somalia to try to attract new recruits. The issue was raised by Jonathan Evans, the head of MI5, in his first interview last month.

In the US, the outgoing head of the CIA, Michael Hayden, has said that Ethiopia's invasion of Somalia in late 2006 “catalysed” expatriate Somalis around the world.

An investigation for Channel 4 News, to be broadcast tonight, also reveals that a suicide bomber who grew up in Ealing is thought to have blown himself up in an attack in Somalia that killed more than 20 soldiers.

The incident is the first reported case involving a Somali based in Britain and will add to pressure on Scotland Yard and the Home Office to tackle the problem within the Somali community, which, at about 250,000 people, is the biggest in Europe.

“Pakistan rightly gets the most attention in terms of external threats,” a senior counter-terrorism source said. “But we believe we should focus more on the Horn of Africa and Somalia in particular.”

Two years ago Ethiopian forces occupied parts of Somalia after ousting the Union of Islamic Courts (UIC) from the capital, Mogadishu – the latest chapter in a long history of conflict between the two countries. The Ethiopians withdrew last month as part of a peace deal agreed between the Government and moderate Islamists, leaving African Union peacekeepers and Somali soldiers – although many believe that they will not be able to keep advancing extremists at bay.

The hardline Islamist militia al-Shabaab, treated as a terrorist organisation by the US, has taken advantage of Ethiopia's withdrawal to boost its control of the south. More than 16,000 people have been reported killed in the past two years of fighting.

Peter Neumann, a terrorism expert who runs the Centre for the Study of Radicalisation at King's College London, told Channel 4 News: “The numbers I hear [going from Britain to Somalia] are 50, 60 or 70, but in reality we don't know. You don't need big numbers for terrorism. Somalia will never become another Pakistan, but that does not mean it is not a threat.”

Most Somalis in Britain entered the country as asylum-seekers within the past 20 years. They include Yasin Omar and Ramzi Mohammed, two of the four men convicted of the botched bombing of the London Underground on July 21, 2005.

An audio message from Osama bin Laden last month urged Muslims to send money or go to fight themselves in Somalia. “Such references are usually a good indicator,” Dr Neumann said. “The place is seen as an opportunity, from a jihadist point of view.”

Some Somali leaders say their community – already associated with gang and knife crime – is being unfairly targeted. But outside a West London mosque last week, several Somalis were adamant that they were entitled to fight for their homeland. “If American troops can go from Arizona to Iraq then someone can leave this area and go to Somalia,” one said.

Jonathan Rugman is diplomatic correspondent of Channel 4 News. His film on Somalia is on at 7pm tonight.

Case study: From business student to suicide-bomber

The British Somali who became a suicide bomber had abandoned a business studies course at Oxford Brookes University (Jonathan Rugman writes). The 21-year-old from Ealing, West London, reportedly blew himself up at a checkpoint in the southern Somali town of Baidoa in October 2007 after crossing into Somalia by foot from Kenya.

News reports at the time said that the Somali Prime Minister was staying at a nearby hotel but escaped. Somali jihadist websites claimed that more than 20 Ethiopian soldiers were killed. The bomber was a member of al-Shabaab – The Youth – militia, which is fighting to impose Islamic law. Its brutal tactics include decapitating alleged spies with knives. Six aid workers were reportedly killed by the group last December.

It is not clear whether Britain's security services are aware of the Ealing student's case. His family, who still live in London, want his name withheld to avoid reprisals.

The man had recorded a martyrdom video in which he urged Somalia's refugee diaspora to join him in his jihad. “Oh my people, know that I am doing this martyrdom operation for the sake of Allah,” he said. “I advise you to migrate to Somalia and wage war against your enemies. Death in honour is better than life in humiliation.”

Sheikh Ahmed Aabi, a moderate Somali religious leader in Kentish Town, northwest London, said that he knew of the Ealing case and had heard from other families of sons travelling to Somalia to join warring Islamist groups. “I'm hearing it from parents,” he said. “They say they [their children] are joining the jihad. I am hearing there are a lot of people. This is a big problem facing our community.”

Failed state

1991 Mohamed Siad Barre ousted as leader, causing civil war

1993 Militias fight US soldiers after shooting down two US army helicopters taking part in an operation to capture the warlord Mohamed Farrah Aidid

2000 Senior figures elect Abdulkassim Salat Hassan as President. Warlords, backed by Ethiopia, vow to set up their own government

2004 Abdullahi Yusuf elected President

2006 Scores killed in worst violence for a decade. Ethiopia invades and fights Union of Islamic Courts, accused of links to al-Qaeda, for control of Mogadishu

2007 Islamic Courts reduced to guerrilla force. A million refugees

2008 Record piracy

January 2009 The Islamist al-Shabaab militia takes control of Baidoa, previously seat of transitional government. Sheikh Sharif Sheikh Ahmed, a moderate, becomes President. Ethiopian forces withdraw

Source: Times archives

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