THE head of MI5 has unleashed a ferocious attack on Vladimir Putin’s Government, accusing it of using a blend of “criminal thuggery”, old-style espionage, cyber-attacks, social media disinformation, military force and “bare-faced lies” to try to undermine the West.

Andrew Parker also noted how Russian state media outlets had promoted at least 30 different "explanations" for the Salisbury nerve agent attack as part of a campaign to shift the blame away from Moscow for the attempted assassination.

And in a speech in Berlin, he warned the threat from the Islamic State "movement" would persist for years to come despite its territorial losses in Iraq and Syria,

In his first public remarks since the poisoning of Sergie and Yulia Skripal, the Director General of the Security Service delivered an unambiguous assessment of who was responsible.

"Whatever nonsense they conjure up, the case is clear," declared Mr Parker.

Vladimir Putin's regime has been the subject of international condemnation since the attack on former double agent in March, which saw the first use of a nerve agent in Europe since the Second World War.

The UK Government has pointed the finger at Russia but Moscow has repeatedly denied responsibility.

Giving the first public speech outside the UK by a serving head of MI5, Mr Parker told an audience of security chiefs in the German capital that Europe faced "sustained threats and sustained hostile activity from certain states".

He explained: "Let me be clear - by this I don't just mean spies spying on other spies, spies following each other around at the dead of night - I mean the deliberate, targeted, malign activity intended to undermine our free, open and democratic societies."

The chief protagonist among such "hostile actors" was the Russian Government, insisted Mr Parker, noting: "Instead of becoming a respected, great nation, it risks becoming a more isolated pariah."

He accused the Kremlin of "flagrant breaches" of international rules, citing the invasion of Crimea, attempts to interfere with democratic elections in the US and France and the unleashing of cyber-attacks as well as the Salisbury episode.

Noting the exploitation of modern technology by Europe's adversaries, Mr Parker said: "Age-old attempts at covert influence and propaganda have been super charged in online disinformation, which can be churned out at massive scale and pace, and at little cost.

"The aim is to sow doubt by flat denials of the truth, to dilute truth with falsehood, divert attention to fake stories, and do all they can to divide alliances.

"Bare-faced lying seems to be the default mode, coupled with ridicule of critics," he argued.

Mr Parker insisted the Russian state had developed a "well-practised doctrine" of blending media manipulation, social media disinformation and distortion, along with new and old forms of espionage, high levels of cyber attacks, military force and "criminal thuggery".

The MI5 chief also said Europe was facing an "intense, unrelenting and multi-dimensional terrorist threat".

Islamic State or Daesh continued to pose the most acute threat yet al Qaeda and other Islamist terrorist groups "haven't gone away", Mr Parker warned.

He added that alongside police, MI5 was also actively "monitoring the trajectory" of extreme right-wing terrorism.

The "unprecedented tempo" of attack planning in Britain showed no signs of abating, he insisted, noting how since the Westminster atrocity in March last year, police and security services had foiled 12 Islamist terror plots.

Meanwhile, Scottish peer Lord Campbell said Mr Parker’s speech showed the need for continued close UK-EU security co-operation despite the ongoing Brexit process.

“Whether over the application of sanctions, fighting terrorism, cross-border crime or anti-piracy, UK-EU collaboration makes us stronger and safer,” insisted the former Liberal Democrat leader.

“Clearly the way to best ensure the security of our country and of our fellow citizens is to maintain the closest possible relationship with Europe. Severing our ties with Europe completely, as the hard Brexit ideologues want us to do, would be reckless in the extreme,” argued Lord Campbell.

The Scot added: “With Brexit looking increasingly like a threat to our security cooperation with our European allies, it is only right that we get a People’s Vote on the terms of the final Brexit deal.”