Poland has repatriated £4billion worth of gold from London to Warsaw in a top-secret operation involving planes, helicopters, high-tech trucks and specialist police.

A total of eight night-time flights were made from an undisclosed London airport over the course of several months this year, transporting 8,000 gold bars weighing 100 tons to several locations in Poland.

The country's gold reserves have been stored at the Bank of England for decades, having been evacuated from Poland at the outbreak of the Second World War amid fears they would fall into the hands of Nazis.

But Poland's nationalist government has now begun repatriating the gold in order to 'strengthen the country'.

Gold bars worth a total of £4billion have been repatriated from London to Warsaw over the last several months in a top-secret operation (pictured being loaded into a crate for transport)

A total of eight late-night flights took off from an undisclosed London airport (pictured) bound for multiple locations in Poland carrying 1,000 bars on each trip

Poland's gold reserves (pictured) were evacuated at the outbreak of the Second World War to stop it falling into Nazi hands, and for decades has been stored at the Bank of England

Security firm G4S International Logistics were given the task of transporting the gold, which it described as one of the biggest movements of gold between banks in the world.

A spokesman said the final trip, which happened on November 22, saw trucks take 20 crates filled with bars from a facility in northwest London to a nearby airport.

The transport was given a police escort and tracked from overhead by a helicopter.

After arriving at the airport, the bars were strapped down inside a Boeing 737 transport plane and flown to two locations in Poland.

The crates were received by an elite police unit and were loaded on to three more armoured trucks before being taken to vaults belonging to Poland's national bank in undisclosed locations.

There, everything was counted and measured to ensure nothing was missing.

Paul Holt, a general manager for G4Si, said: 'It was all very secretive, and extremely important it was done well.'

Poland began increasing its gold reserves in 2018, before announcing that roughly half its store would be transported to Warsaw to 'strengthen the nation'

A fleet of high-tech armoured vans, elite police units, helicopters and planes were used to transport the gold, which was one of the largest transfers between banks in the world

On Monday last week, Poland's bank chief Adam Glapiński announced that the gold transfer had been completed.

He said 100 tons of Polish gold was now securely locked away in the vaults of the NBP Treasury in Warsaw.

A separate press release said: 'To commemorate the return of gold to Poland, the NBP will issue a gold bar-shaped collector coin in December.'

Until recently, Poland held around 100 tons of gold reserves exclusively at the Bank of England, but announced in 2018 that it would buy another 100 tons.

The country then announced it would be repatriating half of the gold, following a similar move by the nationalist government of Viktor Orban in Hungary.

At the time, Glapinski said the gold 'symbolises the strength of the country', boasting that Poland could generate 'multi-billion' dollar profits by selling it - though stressed that he had no plans to do so.

Poland had $121.9 billion in official reserves, including gold, as of October 31 this year, Bloomberg reported.