A cyber attack such as the strike that brought down NHS hospitals in 2017 could prompt a response from all NATO countries, the alliance's general secretary has said.

Jens Stoltenberg revealed that a "serious cyber attack" could trigger Article 5 of the NATO founding treaty.

This commits NATO nations to treating an attack on one member as an attack against all.

The collective defence commitment has been invoked only once in NATO history; by the United States after the 11 September terror attacks in 2001.

In an article for Prospect magazine, Mr Stoltenberg described how NATO was adapting to a "new reality".


"We have designated cyberspace a domain in which NATO will operate and defend itself as effectively as it does in the air, on land, and at sea," he wrote.

"This means we will deter and defend against any aggression towards allies, whether it takes place in the physical world or the virtual one."

The 2017 attack on NHS computers - estimated to have cost the health service nearly £100m - saw malicious software block victims from accessing data and demanded a ransom in exchange for access being returned.

Image: North Korea was blamed for the WannaCry ransomware attack

It also spread worldwide, with Mr Stoltenberg citing it as an example of an attack that can "affect every one of us".

The US, UK and Australia blamed North Korea for the attack

"The 2017 WannaCry virus crippled computers in hospitals across the country, cancelling thousands of scheduled operations and costing the National Health Service millions of pounds," Mr Stoltenberg added.

"Even Nato is not immune to cyberattacks and we register suspicious activity against our systems every day."

The NATO chief boasted of how the alliance is establishing a new Cyberspace Operations Centre in Mons, Belgium, and could also now "also draw from allies' national cyber capabilities for NATO missions and operations".

He praised action by the Netherlands, with the help of British experts, in foiling an attack by Russia on the Organisation for the Prohibition for Chemical Weapons in The Hague.

"No single country alone can secure cyberspace," Mr Stoltenberg said.

"But by cooperating closely, sharing expertise, we will not only survive, but thrive in the new digital age."

He also called for strengthened relationships with industry, as more smart devices become embedded in peoples' lives.

"Cyberspace is the new battleground and making NATO cyber ready-well-resourced, well-trained, and well-equipped-is a top priority as we look towards the NATO summit in London in December and beyond," Mr Stoltenberg concluded.