British youths in the UK could be radicalised as Africa becomes a potential new front for counter-terrorism, a new report has warned.
The radicalisation of British youths seen in some sections of the Pakistani, North African and Indian communities over the last 15 years could spread to a greater extent across Somali communities too, the Royal United Services Institute (Rusi) report said.
The UK cannot expect to remain immune as al-Qaeda, which is weakened following the death of terror mastermind Osama bin Laden in May last year, looks to partnerships in Saharan and sub-Saharan Africa to re-group and re-energise itself, it added.
The report's author, Valentina Soria, said western security and intelligence agencies face new challenges "as jihadism evolves and disperses into territories of ungoverned, or loosely governed, space across large stretches of the African continent".
"Most significant is the potential for radicalisation and then mobilisation of a new subset of British youths," she wrote.
"This has already taken place over the last fifteen years in sections of the Pakistani, North African and even the Indian communities; the UK could soon be facing much greater radicalisation among the Somali minority and new radicalisation in some sections of other communities from east and west African countries."
Ms Soria said foreign fighters now represent "a valuable, albeit still limited, source of manpower for al-Shabaab", a Somali terror group banned in the UK.
It is "possible that the use of new terror tactics may have further alienated its African recruits who are mostly reluctant to get involved in suicide bombings", she said.
"As a result, the recruitment of foreign fighters could be read as a choice of operational necessity rather than as a move aimed to make al-Shabaab the next al-Qaeda."
She added that the "dynamics of jihadism in Africa may provoke direct terrorist attacks inside the UK" but said there had been "no direct public evidence of this happening".
Ms Soria went on: "From west to east Africa, across the sub-Saharan region, we may well be witnessing a new phase of decisive developments that could trigger further turmoil.
"The UK cannot expect to remain immune from the 'spill-over' effects of events that could reshape part of the African continent."
Assessing the threat, the MI5 website states: "Al-Qaeda's affiliates and allies across the world pose an increasing threat to the UK and to UK interests in their regions.
"There is also an underlying, unpredictable threat from people who are inspired, but not trained or directed, by al-Qaeda.
"A significant number of UK residents are training with al-Shabaab, a Somali Islamist militia group, to fight in the insurgency in Somalia. Al-Shabaab is closely aligned with al-Qaeda.
"Somalia shows many of the characteristics that made Afghanistan so dangerous as a seedbed for terrorism in the period before the fall of the Taliban.
"There is no effective government and a strong extremist presence with training camps that attract like-minded extremists from across the world."
It comes after the security service's director-general, Jonathan Evans, said in 2010 that he was "concerned that it is only a matter of time before we see terrorism on our streets inspired by those who are today fighting alongside al-Shabaab".
Last week, the government's drugs advisers were warned that Somali terror groups were targeting youngsters in the UK who have been segregated from society.
Abukar Awale, of community group Somali Diaspora UK, called for advisers to consider the links between khat, a leaf which is chewed, and terrorism in its ongoing review of the drug, which is popular among the East African community in the UK.
Somali communities are concerned that terror groups including al-Shabaab were benefiting financially from the sale of khat and then targeting young people who have been marginalised through their use of the drug, he said.
A government spokeswoman said: "We are tackling the threat of home-grown terrorism with our new Prevent strategy, which is challenging extremist ideology and tackling the radicalisation of vulnerable people.
"We are also working with governments in Africa to improve their capacity to tackle the terrorist threat."