As well as providing logistical support and safe haven for Russian operatives, the family are said to have gathered intelligence and recruited on behalf of Moscow.

Elena, 62, received a secret Russian passport reserved for Unit 29155 members and received the Hero of Russian Federation, the nation’s highest military award, from Putin following sabotage operations in the Czech Republic and Bulgaria.

Nikolay, a former Soviet military officer, caught the attention of Czech investigators because of his role at Imex, an arms company set up to serve European militaries still using Soviet-era hardware.

Their son Pavel, who was once a member of the Czech Pirate Party, a Left-wing movement, also went on to work for the company.

The Czech authorities started looking into the family while they lived a lavish lifestyle despite minimal earnings from Nikolay Šapošnikov’s role as an executive at Imex.

“In some cases their official income could not cover even their phone bill for the month,” the investigators said.

Mrs Šapošnikov owned a company in the Marshall Islands and had two bank accounts in Switzerland, they found.

It was alleged that she had tipped off Gen Averyanov, via his Gmail account, about the whereabouts of weapons intended for shipment to Ukraine, Georgia and Syria. At the time, Russian forces were involved in wars in all three countries.

In October 2014, GRU agents started travelling to the Czech Republic, where they were granted entry to the warehouses in Vrbětice.

On Oct 16 2014, a massive explosion engulfed the facilities warehouse 16, destroying aircraft engines and artillery shells owned by EMCO, another arms company dealing in Soviet-era kit. Two employees at the depot were killed.

A month and a half later, on Dec 3, artillery and mortar rounds, as well as assault rifles, started exploding in another warehouse at the same storage facility.

The Šapošnikovs told police their links to Unit 29155 were “personal” and they did not know members were linked to state terrorism.

They accused authorities of a political persecution because of their Russian background and said that the 2014 explosions in Vrbětice were the result of industrial accidents.