The crisis in Syria has emerged as the biggest threat to Britain’s security, The Telegraph can disclose.
The threat to the UK from returning fighters from the Syrian civil war is now the same as that from al-Qaeda terrorists in the borderlands of Afghanistan and Pakistan.
The increased risk will refocus attention on the decision by David Cameron – backed by MPs in the House of Commons – not to intervene as the Syrian conflict worsened last August.
For the past two years, British jihadists have been able to gain access bomb and weapons training as well as further radicalisation.
There are fears that British men who have been radicalised there are also being encouraged to return to the UK to carry out attacks here rather than staying to fight.
As many as 500 Britons have headed to Syria to fight in the past three years–far higher than the numbers who travelled to Iraq.
The police and security services are understood to be monitoring around half of that number who have returned. Some arrests have been made.
A senior Whitehall source told The Telegraph: “We are seeing a growing threat to the UK from terrorist groups in Syria.
“The threat to the UK comes from a range of countries and groups but Syria is perhaps the biggest challenge right now.”
Confirmation of the escalating concern was made by an additional paragraph to the Government’s assessment on the threat from foreign fighters published on the Security Service’s website.
It says: “Over the last two years, we have seen Syria become an attractive destination for UK extremists wishing to engage in violent jihad.
“The nature of the conflict in Syria and the emergence of the Al Nusrah Front, which has declared its allegiance to Al Qaeda leader Ayman al-Zawahiri, is leading to the country becoming an increasingly significant potential source of future threats to the UK and UK interests overseas.”
Syria is seen as a major threat because of the culmination of a number of aspects that the UK has not faced from one single place before.
Its proximity to Europe makes it easier and cheaper for would-be Jihadists to head there and does not appear as “foreign” as the once-Al-Qaeda strongholds of Afghanistan/northern Pakistan and Somalia or Yemen
Monitoring of terrorists in Syria by British intelligence agencies is made more difficult because of the ease with which they are able to move around the country.
Syria was identified as the “most significant development in global terrorism” in the Home Office annual review of its counter-terrorism strategy Contest this week.
In the foreword to the review, Theresa May, the Home Secretary, said: “We witnessed an unprecedented concentration of the terrorist threat in and from Syria, even as we confronted threats emanating from other countries where it is equally difficult for our nationals security agencies and departments to operate.”
The review went on to warn: “Dealing with terrorism in Syria is a very significant challenge due to the numbers of people fighting with the many Syria based terrorist groups, their proximity to the UK, ease of travel across porous borders and the ready availability of weapons.
“We are concerned about the threat to the UK from Syria based groups and the threat from foreign fighters returning to this country.”
Syria takes up a large proportion of MI5’s international counter terrorism work. Last year Charles Farr, the Home Office’s anti–terror chief, said Syria had become a “game changer”.
Last year the Prime Minister described some of the rebels against President Bashar al-Assad’sregime in Syria as “extremely dangerous terrorists”.
He said: “My concern is that the current trajectory in Syria is very, very damaging. “You have got a dictator who is brutalising his people, who’s using chemical weapons against innocent people.
“You’ve got an opposition elements of which are extremely dangerous extremist terrorists.”