Alexander Lebedev, the Russian billionaire whose son owns The Independent and Evening Standard, tried to help President Putin to win western approval for the annexation of Crimea, according to Kremlin emails leaked this week by Ukrainian hackers.

An email sent from Mr Lebedev’s account to Vladislav Surkov, the Putin aide who engineered the Crimea seizure, proposed a plan to persuade public figures to sign an open letter likening Russia’s action to the Scottish vote on independence. However, unlike in Scotland, in Crimea anti-Russian activists were either arrested or abducted, sometimes turning up dead, and pro-Ukrainian TV stations were shut down.

The letter warned that a third world war could break out if Russia and the West did not set aside their differences over Ukraine