Russia uses migration like a “tap” which it can turn on and off to influence European leaders, experts have said.

Vladimir Putin is accused of using migration as part of his “hybrid warfare” against the West, including as leverage in political support for Ukraine.

It comes as The Telegraph reveals that one of his agents – Jan Marsalek – had been attempting to influence the flow of migrants into Europe using private armies.

There is evidence that Russia is fuelling migration in a number of ways, including physically moving people toward the EU’s borders, supporting smugglers, increasing instability and violence in certain regions including Syria and parts of Africa.

Putin’s cronies are also accused of spreading “fake news” about migration in order to “disrupt European unity”.

Late last year Finland closed the last of its borders with Russia after seeing a dramatic spike in the number of migrants without proper visas and documentation, mostly from the Middle East and Africa.

Elina Valtonen, the Finnish foreign minister, had said that “undoubtedly” Russia was using migration as “hybrid warfare” and in some cases they were “actively helping” migrants travel to the border.

It was just the latest in a string of European countries bordering Russia and its allies which have warned that they have seen a deliberate influx, including Poland, Lithuania, Estonia and Norway.

Frontex, the EU’s border police, said it had seen Russia using migration “as a lever in a larger game of influence and pressure”.

In recent years Putin and his mercenaries have also been increasing their stronghold in key migration routes through sub-Saharan Africa and into Libya – the smugglers’ route through the central Mediterranean.

Russian mercenaries are known to have a presence in Mali, Burkina Faso, and three countries which are a key to migration – Central African Republic, Sudan and Libya.