Sir Keir Starmer's security chief is to face questions in Parliament about the Chinese spying case – but behind closed doors.

Downing Street confirmed yesterday that national security adviser Jonathan Powell will appear before senior MPs and peers amid questions about why the trial of two men accused of passing secrets to Beijing was abandoned.

But his appearance before the Joint Committee on the National Security Strategy will be in private – even though his predecessors have given evidence to the same committee in public.

The decision by Labour ministers – who had previously claimed Mr Powell should not appear at all because he is a special adviser rather than an official – means the public will not hear his response to the allegations that he was involved in top-secret discussions that led to the collapse of the case.

This newspaper can also reveal that the spying suspects may now never face trial because the Crown Prosecution Service has the power to take over a potential private prosecution in order to halt it.