Stephen Parkinson give a "fuller explanation" of why charges against parliamentary researcher Christopher Cash, 30, and academic Christopher Berry, 33, were dropped last month. Both men deny the allegations. Parkinson has blamed the collapse of the case on a failure by the government to provide enough evidence showing China was a threat to the UK's national security. But calls for clarification have grown after the government published witness statements on Wednesday outlining the threat posed by Beijing.

The chairs of four parliamentary committees have given Mr Parkinson, the boss of the Crown Prosecution Service (CPS), until Friday next week to answer a series of questions about why the case collapsed. He is also likely to be hauled before MPs to give evidence, with a joint national security committee of MPs and peers also launching a formal inquiry.

Labour MP Matt Western, who chairs the committee, said there were "many questions yet to be answered" by both Mr Parkinson and the government. Western added that the committee would hope to hear from "the government and officials" as soon as possible. Another parliamentary group, the intelligence and security committee, has launched a separate probe into how classified material was used during the case. (BBC)