The former home secretary, who was in charge of MI5 at the time, said she wanted the case prosecuted and was ‘deeply frustrated’ when it collapsed

To prove the case under the Official Secrets Act, prosecutors would have had to show the defendants were acting for an ‘enemy’

Lord Mark Sedwill, who held the post when Theresa May was in No10, said it was obvious that Beijing constituted a 'threat'.

Simon Case said intelligence chiefs have described China as a threat for years

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The former national security adviser and cabinet secretary said ‘of course’ China is a national security threat to Britain

The former home secretary, who was in charge of MI5 at the time, said she wanted the case prosecuted and was ‘deeply frustrated’ when it collapsed