Sorry kids, I won't be back at school – I'm now the Deputy Prime Minister of Somalia

Six months ago Mohamed Ibrahim was a teacher in north-west London. Every weekday he would commute from his red-brick home in Harlesden to the nearby Newman Catholic College to help Somali children improve their English. Then an unusual job offer came calling. The government of Somalia was asking whether the quietly spoken 64-year-old would be willing to be the war-torn nation's new Deputy Prime Minister.

The job offer, as he explained in a resignation email to his colleagues, was one he could hardly refuse.

"I was unexpectedly called to my country during the summer holidays, at a time when the country is facing a humanitarian crisis such as drought and famine," he wrote. "I will always have Newman College in my heart and won't forget the wonderful colleagues."

The head teacher Richard Kolka remembered the moment the email flashed up on his screen. "I was both amazed and awestruck," he said. "What an honour, but also what a responsibility. I had absolutely no idea he was involved in the political life of his country."

Mr Ibrahim is one of a number of talented, western-educated Somalis who are heeding their government's calls to return to their homeland and rebuild it after decades of civil war.

The mayor of Mogadishu, 55-year-old Mohamoud Ahmed Nur, used to be an employment adviser at Islington council before he returned to the city of his birth three years ago. The current cabinet, headed by the American trained economist Abdiweli Mohamed Ali, was brought in earlier this summer under a UN deal to try and end months of internecine squabbling. It is filled with western-educated Somalis from the United States, Canada and Finland but only one – Mr Ibrahim – is British.

The contrast between Mr Ibrahim's former school and his current workplace could hardly be starker. To reach his office in Villa Somalia, the fortified compound overlooking the battered city of Mogadishu that serves as the government's headquarters, he has to be driven in an armoured convoy through the streets of the world's most dangerous capital.

Even once you are past the sand bags and gun emplacements, Villa Somalia is hardly secure. Fighters loyal to the Islamist al-Shabaab movement routinely target the compound.

And the sheer scale of the problems facing politicians like Mr Ibrahim is daunting. Somalia has been without an effective government for the best part of two decades. The authority of the current cabinet, backed by African Union troops, extends little further than the walls of Villa Somalia. Al-Shabaab, the insurgency that has allied itself with the ideology of al-Qa'ida, controls vast swathes of the country and much of the capital. The Horn of Africa, meanwhile, is in the midst of the worst drought in 60 years and Somalia is at the epicentre. Within weeks of taking up his new post Mr Ibrahim found himself pleading with the international community to rescue Somalia from the abyss.

"The plight of the Somali people is desperate," he said during a conference in Rome. "We have witnessed suffering in the heart of the capital."

Later this month he will travel to the UN General Assembly in New York. According to Mr Kolka, he also intends to pop in on his old school on the way back home. "He was always such a humble guy," he said. "I got the impression he was well-respected by the boys and their Somali parents. But I did not see this coming. I was gobsmacked."