A 34-year-old man who has lived in London for three decades is to be deported to Somalia after a judge said his criminal record qualified him to survive in the war-torn country.

But the family of Abdi Mohamed say sending him back to the east African state would be like signing his death warrant. Mr Mohamed fled persecution in Somalia with his mother and father when he was four and claims to know nothing about the country today.

Since arriving in Britain, he has tried to build a life in north London but took up petty offending to support his drug and alcohol addictions. Mr Mohamed came into contact with law enforcement when he was 12 and later began committing burglaries to buy cannabis and cocaine. His most recent conviction was for an assault on a prison officer, after which the Home Office applied to have him deported to Somalia.

Download the new Independent Premium app Sharing the full story, not just the headlines

Dismissing his appeal, the immigration tribunal judge said: "His experience [criminal activity] will make him more street wise than someone of a similar age who has led a crime-free and more conventional life. These experiences will place him at a distinct advantage in dealing with the circumstances in Somalia and should make it much easier for him to avoid pitfalls."

The judge, James Simpson, said Mr Mohamed's ability to speak English would help him find work and said his family ties here were not strong. But Mr Mohamed said he has always seen himself as British: "The first I knew that I wasn't British was when the judge said I was to be deported after serving my sentence. I couldn't apply for citizenship because I was only a little boy when I came here. I am British not Somalian. I know nothing about Somalia."

Mr Mohamed has been held in an immigration detention centre for 16 months awaiting deportation. Three attempts to fly him to Somalia have been postponed and his family is worried about his physical and mental health. Nothing has been done to regularise his immigration status in Britain, so his criminal record made him liable to detention and deportation under laws for foreign criminals.

Mr Mohamed's two sisters, both teachers in London, are shocked. "It would be like a death warrant for him. Far from surviving, he is not equipped to deal with Somalia and all its problems," said Shukri Mohamed. "Abdi is extremely depressed. He is in limbo. He has been out on bail on three occasions and redetained. This is mental torture. Abdi has served his time but this is double punishment." Amnesty International's Africa Deputy Programme Director Michelle Kagari said: "There is no safety for civilians in Somalia]. Those fleeing violence in Mogadishu are attacked outside and those who reach a camp face violence."

A UK Border Agency spokesperson said: "Where someone is not deemed conducive to the public good we will not hesitate to deport them."

A country in crisis

Much of the world's focus on Somalia in recent weeks has been on the bands of pirates seizing ships and threatening to blow them up. On dry land, the violence and chaos are even more staggering. Two years after being driven from the capital by Ethiopian and Government troops, Islamic insurgents have retaken large areas of the country – 10,000 citizens were killed in the fighting. Last month, a threat to shoot down planes paralysed Mogadishu airport, and almost 40,000 people fled their homes. This week African Union peacekeepers have been targeted. Nearly half of Somalia's eight million people are in need of food aid.