Somalia - The UK could face a growing threat from "lone wolf" terrorists returning from
fighting overseas in the next few years, a think tank has warned.

The Royal United Services Institute estimates about 50 Britons are fighting with Somali
extremists al-Shabab.

Returnees from "wars in Somalia, Yemen or Nigeria" could use their experience on UK
streets, Rusi said.

The Home Office said its security arrangements would reflect "the nature of the terrorist
threat we face".

   It is also feared that the return of Britons from overseas could coincide with the release of
people convicted of terrorist charges over the last decade.

 BBC security correspondent Frank Gardner says the think tank is warning of "a perfect
storm of combined threats coming together in the near future".

The UK terror threat level was reduced from "severe" to "substantial" in July last year, but
Rusi warned that the threat from jihadist terrorism had not diminished.

   Despite recent arrests and failed plots, "lone wolves" and "self-radicalised" jihadi terrorists
were hard to track down and posed a greater security risk, its report said.