CAMPAIGNERS say the death of an Islamic State leader who encouraged British fanatics to attack a North Yorkshire spy base has done nothing to reduce the threat it and residents living nearby face.

Extra security measures and greater vigilance are still needed at RAF Menwith Hill, the largest secret intelligence gathering base outside the US, according to the Campaign for the Accountability of American Bases.

US defence officials said they had a "high level of confidence" that British jihadist Junaid Hussain, 21, who fled from Birmingham to Syria in 2013 while he was on bail, had been killed in a coalition air strike according to US officials.

The strike is thought to have targeted Hussain - who married British ex-punk rock singer Sally Jones following an online romance last year - while he was travelling in a vehicle in Syria.

Hussain's activities have made him a key target for the US military, who included him at number three on a Pentagon "kill list" of IS leaders.

Since escaping to Syria, he is reported to have been an important figure in Islamic State's online recruitment, radicalisation and hacking network.

The announcement comes weeks after Hussain, one of the leaders of the terror group's hacking department, published a Isis hitlist for Britain, which featured four military bases, including the base, locally dubbed The Golf Balls, on the southern edge of the Yorkshire Dales.

Campaigners said while the base near Harrogate had long been known as a potential target for terrorists, it was the first time Isis had confirmed it aimed to launch a lone wolf-style attack there.

Following reports of Hussain's death, Lindis Percy, co-chair of the campaign, said: "I don't think this makes any difference.

"Terrorist groups are like hydra - you chop off one head and another one appears.

"We don't want to be sensationalist, but in this case it is alarming."

A British Government spokesman said: "We are aware of reports that an Isil terrorist of British nationality is believed to have been killed in a coalition air strike in Syria."

Security analysts said it was unclear whether the death of Hussain would lessen the threat of Islamic State attacks on the base or elsewhere in Britain.

Raffaello Pantucci, of the Royal United Services Institute in London, said: “Undoubtedly his online skills will be missed by the group, but it is unlikely to dramatically change the pattern of dangerous plots emanating from the group.”