Russia and Belarus will share a single currency, taxation system and military by the end of the decade, according to annexation papers drawn up by the Kremlin.

The leaked document details how Moscow hopes it will be able to finalise a creeping takeover of its closest ally as part of a larger plan to create a new “Greater Russia”.

Vladimir Putin has long discussed the prospect of recreating Russia’s former, imperialist boundaries by incorporating Ukraine and Belarus into its borders.

The Russian leader invoked the notion of “Greater Russia” in a 5,000-word essay that is now seen as his justification for the war in Ukraine.

The 17-page “internal strategy paper”, first reported by a group of European newspapers, including the Kyiv Independent, was described as “authentic and plausible” by Western intelligence officers.

The Kremlin project to take over Belarus, which became independent from the Soviet Union in 1990, has been in place for almost 24 years.

Until now, the plan, dubbed “Union State”, was largely believed to be an association agreement based on mutual interests.

But according to the paper, Russia will continue to expand its military presence in Belarus until it becomes permanent and the Belarusian army complies with Russian regulations.

Putin’s forces launched a botched attempt to capture Kyiv from within Belarus, but his ally, Alexander Lukashenko, the Belarusian dictator, has refused to join in with the invasion.