Chemical attack fear in North Yorkshire as Isis confirm spy base Menwith Hill is target

Related: Council confident measures will be taken to ensure safety of Menwith Hill workers and residents
June 2015: Calls for closure after base linked to a US drone strike in a non-war zone

The Campaign for the Accountability of American Bases said it was deeply concerning that RAF Menwith Hill, on the southern edge of the Yorkshire Dales near Harrogate, had been confirmed as a target by the terrorist group for a "lone wolf" attack.

The group's co-chair, Lindis Percy, said while a British couple claiming to be Islamic State's hacking division had reportedly encouraged British terrorists to carry out atrocities at the North Yorkshire base, there was a possibility the attack could be chemical, biological or nuclear.

Lindis Percy, co-chair of The Campaign for the Accountability of American Bases

Three other military bases, in Cambridgeshire and Suffolk, featured on an Isis website alongside Menwith Hill - which includes family housing, community facilities and high-technology "golf ball" installations and structures - as well as a list of details relating to military and diplomatic staff.

The online list, which has since been removed, reportedly said: "We are extracting confidential data and passing on your personal information to the soldiers of the khilafah who soon, with the permission of Allah, will strike at your necks in your own lands!"

The hitlist was said to have been compiled to avenge bombing against Muslims in Syria and Iraq.

In July, Junead Ahmed Khan, 24, of Luton, was charged with plotting to running kill US military personnel based in the UK, and attempting to join Islamic State.

Ms Percy, who has spent 25 years campaigning for the closure of the base, which serves primarily as a field station of the US National Security Agency (NSA) to intercept terrorist communications, said: "We have always known that Menwith Hill is a key target for terrorists, but this is Isis.

"No amount of surveillance and patrols will prevent an attack as the base has a four-mile perimeter, so it puts all our security at risk."

Ms Percy said it was concerning the threat of a Fusilier Lee Rigby-style outside a military base had emerged during the summer Parliamentary recess as security questions could not be raised by MPs.

A Ministry of Defence spokeswoman said: "We would not issue a comment about our security response for obvious reasons."

It is understood threat levels facing the base are continually monitored, with levels of protection increased as required.

The NSA did not respond to a request for a comment on what action it had taken.

Brief history of RAF Menwith Hill

1960 - Opened as Menwith Hill Station after land is leased by the Crown to the US 1966 - US civilians join the station as responsibility passes to the National Security Agency.

1978 - First 'golf ball' constructed

1980s - The number of US personnel at the station doubles to an estimated 850. Regular protests are held outside the base amid heightened Cold War paranoia and permanent 'peace camps' are set up.

1991 - Plays a role in tracking Iraqi communications during the first Gulf War

1996 - Site is renamed RAF Menwith Hill, bringing it into line with other US bases in the UK.

2002 - Administrative responsibility transferred from the US Army to the US Air Force Intelligence Agency

2007- Two elderly peace activists are found guilty of trespassing at the site

2009 - Staff now number 1,840

2014 - US announces plans to cut 500 military and civilian posts at base

2015 - Calls for the closure of the site after it emerged the base had been linked to US drone attacks in non-war zones.