Alexei Navalny said proposals outlined by the prime minister would only play into President Putin’s hands

Russia’s main opposition leader has called on Theresa May to punish the Kremlin for the poisoning of Sergei Skripal by moving against politicians and business leaders with assets in the UK.

Alexei Navalny, 41, said that the tycoons Roman Abramovich and Alisher Usmanov should come under scrutiny, as well as Igor Shuvalov, a wealthy deputy prime minister of Russia with assets in London.

Mr Navalny said that measures being proposed by MPs such as banning the Kremlin television channel, RT, in Britain and a boycott by officials of the World Cup in Russia would play into President Putin’s hands.

He added that all his arguments were predicated on the UK proving that Russia was involved in the attempted murder of Mr Skripal, 66, and his