Mr Schroeder told a discussion forum hosted by Germany’s Die Zeit newspaper that as someone who was aware of history, Mr Putin had certain justifiable “ fears about being encircled” and that since the end of the Cold War there had been “ unhappy developments” on the fringes of what was once the Soviet Union.

He also claimed that the European Union appeared not to have “ the remotest idea” that the Ukraine was “culturally divided” and had made mistakes from the outset in its attempts to reach an association agreement with the country.

Mr Schroeder accepted that Russia’s intervention was in breach of international law but compared the Kremlin’s action to his own government’s military support for the NATO bombardment of Serbia during the Kosovo crisis in 1999.

“We sent our plans to Serbia and together with the rest of NATO they bombed a sovereign state without any UN security council backing,” Mr Schroeder insisted, adding that he had since become cautious in apportioning blame.

Mrs Merkel has described Mr Schroeder’s claims as “shameful”. She told the German parliament that there was “no way” that the Kosovo crisis could be compared with Russia’s intervention in Crimea.

An attempt by the German Green Party to ban Mr Schroeder from speaking in public about Ukraine was narrowly defeated in the European parliament on Thursday.