ES News email The latest headlines in your inbox twice a day Monday - Friday plus breaking news updates Enter your email address Continue Please enter an email address Email address is invalid Fill out this field Email address is invalid You already have an account. Please log in Register with your social account or click here to log in I would like to receive lunchtime headlines Monday - Friday plus breaking news alerts, by email Update newsletter preferences

A purge of potential terrorists working on London’s transport system is being carried out to protect the public from another Islamic State attack, Britain’s security minister revealed today.

Ben Wallace said that extremists who “would pose a risk to London and its transport network” had already been removed from their posts during an intensive drive to identify potential attackers.

He revealed that the new action was intended to help police and the intelligence agencies cope with the “acute” threat and suggested that further removals would take place as part of the continued effort to disrupt would-be terrorists before they could strike. His comments came during an interview with the Evening Standard in which Mr Wallace also disclosed that:

Some foreign fighters from Britain were “re-engaging” in the conflict in Syria and only a “tiny” number were attempting to return.

“A number” of other UK Islamists were detained in Syria in addition to the two so-called “Beatles” Alexander Kotey and El Shafee Elsheikh held by Kurdish fighters.

In Britain, IS and far-Right extremists have been grooming people with autism to turn them towards violence.

But his most significant comments were on the ongoing effort to remove potentially dangerous extremists from jobs on London’s transport network and in other “sensitive” areas.

The problem was highlighted following the London Bridge attack last year when it emerged that Khurram Butt, one of the three killers, had previously worked for London Underground.

Mr Wallace said that with about 3,000 terror suspects under active scrutiny and a further 20,000 logged as former “subjects of interest”, police and MI5 needed other methods, beyond arresting suspects, to keep the public safe. Disrupting potential attackers through early intervention was one way, particularly when they could use their jobs for malign purposes. “We’ve done a lot of work over the last year about people working in sensitive areas who shouldn’t be, and removing their ability to do so,” Mr Wallace said.

“It’s reducing the insider threat. There are definitely people who have worked in sensitive areas that we have now removed who would pose a risk to London and its networks of transport.

“We’ve got to protect as well as pursue. There are more things we can do around where these people work.” Mr Wallace said that other methods to disrupt potential terrorists included targeting them through immigration powers or welfare policies.

He added: “We have an acute number of people in this country who are attracted to extremism or violent extremism. You can’t arrest your way out of that so you have to develop a way that you can early intervene with some people. Disruption is really important.

“There are some people whose immigration status may be rightly examined to remove them from threat and there are people involved in normal crime who we could take off the streets. There are people who have social issues — are they neglecting their families, are they a troubled family that the troubled family scheme could deal with, are they being exposed to non-regulated school settings?

“We seize a number of these people who have autism, who are targeted and groomed by IS and the far-Right — so are we doing enough in mental health to identify vulnerable people?”

On UK foreign fighters, Mr Wallace said that “not many are trying to get back” and that any “hard nasties” who tried would struggle to succeed “any time soon”. He added: “We thought a lot would start coming back when IS imploded. That hasn’t happened. We’ve seen tiny dribs and drabs, predominantly women with their children, usually in the straightforward position of they’ve been arrested by the Turks and the Turks are deporting them... There haven’t been the hard nasties turning up in that way.”

Others had decided to “re-engage in the battle front” in Syria or Iraq and would “fall under the Coalition effort”.

For those detained by Kurdish forces, Britain was working to ensure that they faced justice, but was taking care to ensure that legal process was followed to avoid any future risk of human rights litigation and compensation claims.

Mr Wallace said the Government was exploring options for the two IS “Beatles” to face trial for their alleged roles in the torture and killing of hostages.

“We are working with our allies, with America, with Iraq, our police here... they are in the custody of the Kurdish militias so there is more to run on that.”