Lord Janner, who died in December 2015, is accused of abusing boys in children’s homes in Leicestershire where he was an MP.

His children have branded the inquiry into their father a witch hunt, pointing out he was never convicted in his lifetime and that now he is dead he cannot defend his reputation.

They also point out that the Independent Inquiry into Child Sexual Abuse (IICSA) was set up to investigate institutional abuse and that Lord Janner is the only individual who has merited an investigation strand of his own.

Welcoming the decision, his son Daniel Janner QC said: “It gives me the chance to undermine my father's strand of the inquiry from within. It is a macabre show trial.”

Mr Janner added: “Our Core Participant status does not legitimise an utterly disgraceful and unjust process.