A victim of historical child sexual abuse has launched a legal challenge to the choice of Fiona Woolf as the chair of the inquiry investigating the issue.
A judicial review application, seen by the BBC, claims she is not impartial, has no relevant expertise and may not have time to discharge her duties.
Labour wants Mrs Woolf to meet abuse victims amid concerns over her links to former Home Secretary Lord Brittan.
Downing Street said it had “full confidence” in her doing the job.
BBC assistant political editor Norman Smith said he believed the government would do everything it could to “cling onto” Mrs Woolf given that her predecessor in the role had already stood down and the inquiry was being asked to produce an interim report by the end of March.
Questions have been asked about Mrs Woolf’s suitability for the role given that she has no experience in child protection or family law and on Tuesday revealed that she had dined with Lord Brittan – home secretary in 1984 when ministers were handed a dossier on alleged high-profile paedophiles – five times since 2008.
The legal challenge to her appointment could be heard before the end of the year.
Judicial review is used to challenge the decisions of government and other organisations based on the law. Most applications do not get past the initial stage and are rejected by a judge.
‘Lack of confidence’
The application comes amid calls from a number of MPs from different parties for her to consider her position.
Lib Dem MP John Hemming said Mrs Woolf’s personal contacts “would give no confidence to the victims that have been ignored for many years”, while Conservative Nadine Dorries tweeted that Mrs Woolf “no longer” had full public and victim confidence.