Vladimir Putin has said Britain's next prime minister should "forget about" the poisoning of a former Russian spy on British soil last year and move on to rebuilding relations between London and Moscow.

Relations between Russia and the UK collapsed in March 2018 after Sergei Skripal and his daughter Yulia were found in critical condition on a park bench in the town of Salisbury.

It was determined the two were poisoned with a Soviet-designed nerve agent, known as Novichok, in an attack blamed on the Russian government.

Russia has repeatedly denied any involvement, throwing out an array of alternate theories -- including that British secret services synthesized Novichok at the nearby Porton Down chemical weapons laboratory and framed Russia for the attack to undermine its image.

The US and a number of other Western countries agreed with the UK’s assessment and joined in accusing Russia of the poisoning.