pact

But throughout the war, both sides have taken care to avoid turning the conflict into a direct battle between Russia and NATO, whose 32 member nations, including the United States, have a mutual-defense pact.

But there is no doubt that the pair have stepped up cooperation after signing a security pact in June to help each other in the event of "aggression" against either country.

The UK already has a defence pact with France – the Lancaster House Treaty which was signed in 2010 by David Cameron and Nicholas Sarkozy – but this is the first with Germany.

Last week, Putin introduced a bill to ratify the pact.

Earlier this week, Putin introduced a bill to ratify a military pact he made with Kim, which pledges that Russia and North Korea will help each other in the event of "aggression" against either country.