The battle plan, said to be contained in top secret documents obtained by The Daily Telegraph, recommended re-arming up to 100,000 German troops to help half a million British and US soldiers fight their erstwhile wartime ally.

The 29-page report, code-named `Operation Unthinkable', was presented to Churchill on May 22, 1945, 14 days after the end of the Second World War in Europe, according to the London newspaper.

It assumed that the Third World War would start on July 1, 1945, probably with a surprise attack by 47 British and American divisions between Dresden and the Baltic, the daily said.

Stalin in retaliation was expected to invade Turkey, Greece, Norway and the oilfields of Iran and Iraq; and launch extensive sabotage operations in France and the Netherlands.

Butthe War Cabinet plan ruled out ``total war'' against the Red Army, which outnumbered the allies by more than two to one, adding that there was no reason why an Anglo-American invasion of Russia would fare any better than Hitler's Operation Barbarossa.

The documents, discovered in Britain's Public Records Office, showed that planning was carried out at the very highest level of the British government and military, said The Daily Telegraph.

Churchill described the plan as ``a purely hypothetical contingency'' but nonetheless set his planning staff to work on it amid the euphoria of victory.

He eventually rejected the plan on the advice of the Chiefs of staff and replaced it with a defensive scheme to guard against invasion by the Red Army, the newspaper said.