Somalia's al-Shabab defectors

It is nearly four years since the militant group al-Shabab was driven out of the Somali capital, Mogadishu.

Since then it has lost much of the territory it once controlled, but it retains the ability to carry out high-profile attacks - both inside Somalia, and in neighbouring Kenya.

The government of Somalia however says it is weakening the top leadership of al-Shabab through a combination of American drone strikes, and an amnesty programme for high-level defectors.

Africa correspondent Andrew Harding has been in Mogadishu - where he had exclusive access to one former al-Shabab commander.