A number of Russian spies have been sanctioned for conducting a "sustained campaign of malicious cyber activity" including in the UK, the Foreign Office has said.

The UK government sanctioned 18 people it named as spies from Russia’s GRU military intelligence agency who it said were responsible for conducting cyber and hybrid warfare operations against Britain and Ukraine.

Britain said on Friday it had discovered a sophisticated digital espionage tool and sanctioned more than 20 Russian spies, hackers and agencies over what it called a "sustained campaign of malicious cyber activity" targeting governments and institutions across Europe.