Nato’s most senior British officer has claimed that alleged Russian cyber attacks could be deemed an act of aggression and trigger the military alliance’s principle of collective defence.

General Sir Adrian Bradshaw, the Deputy Supreme Allied Commander Europe, said allegations of interference in American and European elections and an international disinformation campaign could cause the definition of an “attack” to be widened.

Nato’s founding treaty states that “an armed attack against on or more [members] shall be considered an attack against them” and allow allies to take any action deemed necessary in self defence.

General Bradshaw said the article, number five, would come into effect “when it’s declared to be”.

“It is a political decision, but it is not out of the question that aggression, blatant aggression, in a domain other than conventional warfare might be deemed to be Article Five,” he told The Times.

The measure was used for the first time after the 9/11 terrorist attacks in New York and Nato has also invoked collective defence over the Ukrainian and Syrian civil wars.

When the treaty was drawn up, Nato’s primary aim was to counter the risk of the Soviet Union expanding through Europe.

Nato has increased the troops deployed along its eastern flank (Getty) (NATALIA DOBRYSZYCKA/AFP/Getty Images)

But almost 70 years on, the alliance’s focus has expanded to hybrid warfare, including cyber attacks and hacking, which has sparked the creation of a dedicated Nato online defence force.

General Bradshaw said Nato has “declared cyber as a domain in warfare, alongside air, maritime, special forces and land”.

“It’s a growing area,” he told an event held by the Council on Foreign Relations in January.

“It is hard to imagine any future conflict that doesn’t include a substantial cyber element.

“It’s certainly a big part of our potential threat from both Russia and from Islamist extremists.”

The commander, who is to be replaced by Lieutenant General Sir James Everard later this month, said Russia posed a “hybrid threat” to Nato members.

Russian military activity in Crimea Show all 11 1 /11 Russian military activity in Crimea Russian military activity in Crimea Ukraine-russian13-ap.jpg Russian, right, and Ukrainian navy sailors are deployed outside a Ukrainian Coast Guard base in Balaklava near Sevastopol, Crimea (AP) AP Russian military activity in Crimea Ukraine-russian9-ap.jpg An unidentified armed man patrols a square in front of the airport in Simferopol, Ukraine (AP) AP Russian military activity in Crimea Ukraine-russian12-ap.jpg A soldier rests atop a Russian armored personnel carriers with a road sign reading "Sevastopol - 32 kilometers, Yalta - 70 kilometers", near the town of Bakhchisarai, Ukraine (AP) AP Russian military activity in Crimea Ukraine-russian11-rtp.jpg Armed Russian navy servicemen surround a Ukrainian border guard base in Balaclava, in the Crimea region (Reuters) Reuters Russian military activity in Crimea Ukraine-russian10-afpgt.jpg Unidentified soldiers block a road to Ukrainian military airport Belbek not far from Sevastopol (AFP/Getty Images) AFP/Getty Images Russian military activity in Crimea Ukraine-russian7-rt.jpg Sea gulls perch onboard a Russian military vessel anchored at a navy base in the Ukrainian Black Sea port of Sevastopol (Reuters) Reuters Russian military activity in Crimea Ukraine-russian6-afpgt.jpg Activists of the Russian Bloc party guard the road to Ukrainian military airport Belbek not far from Sevastopol (AFP/Getty Images) AFP/Getty Images Russian military activity in Crimea Ukraine-russian8-rt.jpg Ukrainian police walk near the Crimean parliament building in Simferopol. Ukraine said on Thursday it would regard any movements by Russian military in Crimea outside the Russian Black Sea fleet's base in Sevastopol as an act of aggression. (Reuters) Reuters Russian military activity in Crimea Ukraine-russian-navy1-rt.jpg Armed Russian navy servicemen surround a Ukrainian border guard base in Balaclava, in Crimea region (Reuters) Reuters Russian military activity in Crimea Ukraine-russian4-ap.jpg An unidentified gunman holds his assault rifle ready while he and others block the road toward the military airport at the Black Sea port of Sevastopol in Crimea (AP) AP Russian military activity in Crimea Ukraine-russian3-ap.jpg A local resident smiles preventing people from going too close to unidentified gunmen blocking the road toward the military airport at the Black Sea port of Sevastopol in Crimea (AP) AP

“It’s not just the threat of overt military attack, but it’s a raft of other measures, including covert, paramilitary, and non-military activities, some of which will be coordinated by the intelligence arms of Russia,” General Bradshaw added.

“And we as Nato need to have our antenna tuned to the signs that this sort of hostile activity is going on.”

He accused the Kremlin of “showing a proclivity to disobey the rules of international relations” with its military incursion into Crimea and alleged backing for rebels in eastern Ukraine.

“We need to put in place thoroughly effective and convincing deterrence so that everybody knows where the red lines are,” General Bradshaw said.

“We are effectively building and sustaining military capability so that we never have to use it.”

His comments came amid an ongoing storm over Russia’s alleged interference in the US election in favour of Donald Trump.

The President has defended Russia against his own intelligence agencies’ allegations of involvement in the Democratic National Committee cyber attacks, and other leaks and “fake news” spread to damage Hillary Clinton.

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“We assess Russian President Vladimir Putin ordered an influence campaign in 2016 aimed at the US presidential election,” said a report released by the Office of the Director of National Intelligence.

“Russia’s goals were to undermine public faith in the US democratic process, denigrate Secretary Clinton and harm her electability and potential presidency.

“We further assess Putin and the Russian Government developed a clear preference for President-elect Trump.”

European intelligence agencies have warned attempts could also be made to influence upcoming votes in France, the Netherlands and Germany.

A recent report by the House of Commons Foreign Affairs Committee said the “rise of fake news” emanating from Russia was also a concern, questioning the impartiality of state-owned outlets Russia Today and Sputnik.

The Kremlin has denied all allegations of attempting to influence international elections or waging a disinformation campaign, while accusing Nato and the West of engaging in a “propaganda war” against it and warmongering with increasing military deployments and drills in eastern Europe.