THEY were known as Unit 26165.

The four members of the supposedly crack Russia team of military spies were supposed to slip into the country, carry out their secret mission and then slip out again. Undiscovered.

However, their mission to target the world chemical weapons watchdog turned out to be anything but a slick Bond-style operation.

The GRU team was caught "in flagrante" as its members attempted to hack into the computer system of the Organisation for the Prohibition of Chemical Weapons[OPCW] in The Hague. This was the international organisation testing the chemicals used in the Salisbury poisoning and which turned out to be Novichok, a nerve agent created in Russia during the Soviet era.

But once exposed, the Kremlin’s spies were sent packing back to Moscow by Dutch security services, leaving behind them a treasure trove of intelligence about their covert activities.

The Dutch operation followed just weeks after the attempted assassination of former Russian spy Sergei Skripal in Salisbury in March by two fellow GRU officers.

In the days and weeks that followed, British officials said Russia spy teams attempted to hack the computers of the Foreign Office and the science laboratory at Porton Down, which was, of course, investigating the deadly nerve agent used in Salisbury.

When the GRU’s spear-phishing attempts at the headquarters of the OPCW failed, its chiefs ordered Unit 26165 to go to the Netherlands to see if they could have more luck.

Yet right from the start they appear to have made little attempt to hide their presence in the country, arriving together with Russian diplomatic passports at Schiphol Airport, where they were captured on CCTV being met by a Russian embassy official.

Once through customs and immigration controls, the Russian team hired a car and headed for The Hague. Three days later, on April 13, the vehicle parked up close to the OPCW building.

It was there the Dutch security service - operating with the assistance of British intelligence - pounced.

The GRU men were said to have tried to destroy their equipment but were prevented from doing so.

In the back of their car, investigators found - partially hidden under a coat - a computer connected to a 4G mobile and a Wi-Fi panel antenna, as well as other specialist hacking equipment together with maps and 20,000 euros and 20,000 dollars - in cash.

Helpfully for the UK and Dutch investigators, taxi receipts were found showing a journey from a GRU facility in Moscow to the airport.

There was more. Train tickets to Basel were also found together with evidence of online searches for the Spiez lab, Switzerland’s institute for nuclear, biological and chemical protection, which is based in the city.

While the GRU team was being escorted back to Schiphol for its return to Moscow, investigators began going through the recovered laptop, which revealed Google searches relating to the OPCW building and its surroundings. A camera also contained reconnaissance photos of the area.

Remarkably, the investigators also found computer evidence of one of the Russian spy’s involvement in other GRU spy operations, including in Malaysia, where he is said to have targeted the investigation into the shooting down of flight MH17 over Ukraine in 2014 when almost 300 people died.

There was also evidence of his involvement in the hacking of in the World Anti-Doping Agency in Switzerland, which was investigating widespread doping by Russian athletes, and even a photograph of one spy happily posing with a young woman at the 2016 Olympics.

One UK security official noted: "For GRU officers, to get caught in this way would be considered a pretty bad day."