MI5 head warns of serious risk of UK terrorist attack
The UK faces a continuing serious risk of a lethal terrorist attack taking place, the head of MI5 has warned.
Jonathan Evans raised concerns over the number of soon-to-be-freed inmates who are "committed extremists and likely to return to terrorist activities".
He also said Somalia and Yemen were important concerns for MI5, as a source of serious plots against the UK.
And, he said, the security service had not expected dissident republicanism to grow as it had in Northern Ireland.
Mr Evans, who made the rare public remarks to the Worshipful Company of Security Professionals in London, said dealing with international terrorism remained the main focus of MI5's efforts.
"Counter-terrorist capabilities have improved in recent years but there remains a serious risk of a lethal attack taking place. I see no reason to believe that the position will significantly improve in the immediate future," he said.
He said hundreds of officers were involved in an "intense struggle", largely out of sight of the public.
Every month, hundreds of new leads come into MI5 headquarters at Thames House from various sources, with only sufficient resources to investigate those that appeared to be high priority, Mr Evans said.
"At any one time we have a handful of investigations that we believe involve the real possibility of a terrorist attack being planned against the UK," he said.
One concern is that a number of individuals, convicted of offences in the years after the 9/11 attacks, are now coming out of prison having served their terms.
"We know that some of these prisoners are still committed extremists who are likely to return to their terrorist activities," Mr Evans said, adding that they would be added to the cases that needed to be monitored.
He said another change in recent years was the source of the most serious plots.
In previous years, officials have said that 75% of priority plots had links to Pakistan. That figure has now dropped to 50%.
This was partly because of pressure on al-Qaeda leadership operating in Pakistan's tribal areas, but it was also a sign of a diversifying threat, he said.
Mr Evans said in Somalia there were a "significant number of UK residents training in Al Shabaab camps" to fight in the country.
"I am 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," he warned.