Britain’s archaic treason laws could be updated to enable the prosecution of those who leak secrets to “hostile states”. The move comes amid concern about the activities of Russia and China in the West.

The government announced in the Queen’s Speech that it was “considering the case” for updating Britain’s 650-year-old treason laws as part of a new espionage bill.

Revising the Treason Act of 1351, which has not been used since 1945, would enable the government to prosecute anyone who participates in “harmful activity” with a foreign state.

The legislation is being drawn up after the poisoning last year in Salisbury of a former Russian spy, Sergei Skripal, and his daughter, Yulia. Ministers blamed Russia for attacking the pair with a powerful nerve agent.