Russian spies are “constantly” trying to hack UK government networks and critical national infrastructure, officials have warned after thwarting a series of cyberattacks following the Salisbury poisoning.

British, Dutch and American authorities named Russia’s GRU military intelligence agency as the culprits behind a “close access” attempt to compromise the Organisation for the Prohibition of Chemical Weapons (OPCW).

Officials said they had also foiled cyberattacks on the Foreign Office and Porton Down defence laboratory in the wake of the Skripal poisoning in March.

They said that because the “spear phishing” attack, where hackers attempt to fool recipients into opening malicious emails by posing as someone else, did not work, they are unsure what the Russians wanted to do.

Other attacks have been aimed at intercepting and monitoring communications, gaining information or disrupting systems and operations.

A senior government official, who spoke to journalists including The Independent on condition of anonymity, said British authorities, institutions and companies were being attacked “all the time” and the OPCW plot was part of a much wider campaign.

“Russian intelligence services are constantly conducting operations that to try to compromise UK government networks and critical infrastructure,” he added.

Dutch security services expel Russian spies over cyber plot Show all 23 1 /23 Dutch security services expel Russian spies over cyber plot Dutch security services expel Russian spies over cyber plot Russian passports belonging to (top row) Oleg Sotnikov (left), Aleksei Morenets, (bottom row) Evgenii Serebriakov (left) and Alexey Minin, who have been named as the four GRU officers who tried to hack the global chemical weapons watchdog which is investigating the Salisbury nerve agent attack PA Dutch security services expel Russian spies over cyber plot On April 13 the officers parked a car carrying specialist hacking equipment outside the headquarters of the OPCW in The Hague Dutch Ministry of Defence/PA Dutch security services expel Russian spies over cyber plot Specialist equipment intended for the alleged hacking of WiFi networks of the Organisation for the Prohibition of Chemical Weapons (OPCW). Russia's military intelligence service has been accused of trying to hack the global chemical weapons watchdog which is investigating the Salisbury nerve agent attack PA Dutch security services expel Russian spies over cyber plot The Dutch counter-terrorism officers intervened to disrupt the operation and the four GRU officers were ordered to leave the country Dutch Ministry of Defence/PA Dutch security services expel Russian spies over cyber plot Mobile phones and a camera recovered from four GRU officers who were alleged to have hacked the WiFi networks of the Organisation for the Prohibition of Chemical Weapons (OPCW) PA Dutch security services expel Russian spies over cyber plot The four Russians arrived on diplomatic passports Netherlands Defence Ministry Dutch security services expel Russian spies over cyber plot Alexey Minin, who has been named as one of the four GRU officers who tried to hack the global chemical weapons watchdog which is investigating the Salisbury nerve agent attack PA Dutch security services expel Russian spies over cyber plot A car carrying hacking equipment used by GRU officers, travelling on official Russian passports, parked near the headquarters of the OPCW in The Hague Dutch Ministry of Defence/PA Dutch security services expel Russian spies over cyber plot Oleg Sotnikov, who has been named as one of the four GRU officers PA Dutch security services expel Russian spies over cyber plot Hacking equipment belonging to four Russian officers Dutch Ministry of Defence/AP Dutch security services expel Russian spies over cyber plot Evgenii Serebriakov, who has been named as one of the four GRU officers PA Dutch security services expel Russian spies over cyber plot Equipment found in possession of four Russian citizens Reuters Dutch security services expel Russian spies over cyber plot Photos of the Organisation for the Prohibition of Chemical Weapons (OPCW) and its surroundings taken on the 11 April, found on the phone of GRU officer Alexey Minin Dutch Ministry of Defence/PA Dutch security services expel Russian spies over cyber plot Equipment found in possession of four Russian citizens REUTERS Dutch security services expel Russian spies over cyber plot Aleksei Morenets, who has been named as one of the four GRU officers PA Dutch security services expel Russian spies over cyber plot Undated handout photo dated issued by the Dutch Ministry of Defence of a car carrying hacking equipment used by GRU officers, travelling on official Russian passports, parked near the headquarters of the OPCW in The Hague. PRESS ASSOCIATION Photo. Issue date: Thursday October 4, 2018. On April 13 the officers parked a car carrying specialist hacking equipment outside the headquarters of the OPCW in The Hague. At that point the Dutch counter-terrorism officers intervened to disrupt the operation and the four GRU officers were ordered to leave the country. See PA story POLITICS Russia. Photo credit should read: Dutch Ministry of Defence/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder. Dutch Ministry of Defence Dutch Ministry of Defence/PA Dutch security services expel Russian spies over cyber plot A combo of a taxi bill and a map, with a ride from a street next to the Main Directorate of the General Staff of the Armed Forces of the Russian Federation, GRU, to Sheremyetevo airport in Moscow, found in possession of one of four GRU officers AP Dutch security services expel Russian spies over cyber plot Yevgeny Serebryakov, an alleged Russian agent AFP/Getty Dutch security services expel Russian spies over cyber plot Dutch security services say they have foiled an attempted cyber attack targeting the international chemical weapons watchdog, during its investigations into the Salisbury attack. Netherlands Defence Ministry Netherlands Defence Ministry Dutch security services expel Russian spies over cyber plot Dutch security services say they have foiled an attempted cyber attack targeting the international chemical weapons watchdog, during its investigations into the Salisbury attack. Netherlands Defence Ministry Netherlands Defence Ministry Dutch security services expel Russian spies over cyber plot Dutch security services say they have foiled an attempted cyber attack targeting the international chemical weapons watchdog, during its investigations into the Salisbury attack. Netherlands Defence Ministry Netherlands Defence Ministry Dutch security services expel Russian spies over cyber plot Dutch security services say they have foiled an attempted cyber attack targeting the international chemical weapons watchdog, during its investigations into the Salisbury attack. Netherlands Defence Ministry Netherlands Defence Ministry Dutch security services expel Russian spies over cyber plot Dutch security services say they have foiled an attempted cyber attack targeting the international chemical weapons watchdog, during its investigations into the Salisbury attack. Netherlands Defence Ministry Netherlands Defence Ministry

“We’re learning from events like this – it’s a demonstration that we are able to track and disrupt these activities but we have to continue to be vigilant.

“There was a huge amount of cooperation and effort that went into identifying and disrupting this [OPCW plot] and I certainly wouldn’t underestimate their capabilities.”

The official could not confirm that all previous attempted cyberattacks had been foiled but said security services “disrupt everything we see”.

“The GRU is testing the strength of the west’s intelligence services and there is a message here about our capabilities,” he added.

The briefing was part of a wave of announcements in Britain, the Netherlands and US naming the GRU responsible for global cyberattacks committed by groups going by names including APT28, Fancy Bear, Sofacy, Sandworm and CyberCaliphate.

Incidents listed by the UK government include attacks on Ukrainian infrastructure, the Democratic National Committee, anti-doping agencies and authorities investigating the downing of flight MH17.

As Nato and other countries backed calls for accountability, British authorities said the public disclosures aimed to make collaboration between allies “more evident to the wider world”.

A second government official said the timing and targeting of operations suggested that when there are international investigations into Russian activity, the “GRU seems to deploy”.

Inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) arrive to begin work at the scene of the nerve agent attack in Salisbury (Reuters/Peter Nicholls) (REUTERS/Peter Nicholls)

“This [announcement] is not with an aim to escalate – there is no quibble at all with the Russian people – but to deter this activity and defend ourselves,” she added.

Asked whether the UK was going to hit back at Russia with similar tools, she said that British intelligence agencies could not be “put in the same moral and ethical bucket”.

British officials say they do not know how Russia will react to the latest revelations, but are expecting a fresh swell of disinformation and conspiracy theories.

The Kremlin reacted angrily to the allegations, dismissing them as “fantasies” amid heightened tensions over the attempted assassination of Sergei Skripal in Salisbury.

British authorities named two GRU agents as the culprits and issued international warrants for their arrest over the poisoning and later death of Dawn Sturgess, who came into contact with a discarded bottle of novichok.

The substance used was tested at the Porton Down laboratory, before the OPCW took additional samples to verify the presence of novichok.

The four GRU agents travelled to the watchdog’s headquarters in the Netherlands amid work on the Salisbury samples, while the OPCW was also due to analyse chemical weapons allegedly used by Russia’s ally Bashar al-Assad in Douma.

They were caught outside the OPCW’s headquarters in a hire car carrying specialist equipment to hack wifi networks on 13 April.

Equipment found with four GRU officers arrested outside the OPCW headquarters in April (PA)

Dutch investigators said the spies attempted to destroy their equipment and phones as police moved in but did not succeed, leaving an unprecedented haul of intelligence that has since been used to uncover their other activities.

Ticket purchases and internet searches showed that they later intended to travel onwards to the OPCW-accredited Spiez laboratory in Switzerland, which was testing novichok samples from Salisbury at the time.

The Russian men taken into custody, travelled under the names Aleksei Sergeyvich Morenets, Evgenii Mikhaylovich Serebriakov, Oleg Mikhaylovich Sotnikov and Alexey Valeryevich Minin.

They had arrived in The Hague three days earlier on diplomatic passport and investigators at Bellingcat and The Insider said the identities listed were real, rather than aliases used as cover.

Two of the passports – for the “cyber-operators” involved – were issued on the same day in April 2017 and have numbers just one digit apart.

The two GRU assassins who poisoned Mr Skripal in Salisbury were found to be travelling on fake passports that were three digits apart.

In a joint statement, Theresa May and Dutch prime minister Mark Rutte said the GRU had shown “disregard for the global values and rules that keep us all safe”.

“The GRU’s reckless operations stretch from destructive cyber activity to the use of illegal nerve agents, as we saw in Salisbury,” they added.