Two judges involved in a high-profile blackmail trial are to be investigated by the judicial watchdog.
Neither judge will sit during the investigations
Immigration judges Mohammed Ilyas Khan and his female colleague - known only as Judge J - will be investigated by the Office for Judicial Complaints.
Brazilian cleaner Roselane Driza worked illegally for both judges. Both said they were unaware of her status.
The lord chancellor said there was particular concern over the issue of hiring an illegal worker.
The lord chancellor and lord chief justice decided there were "sufficient grounds" for a preliminary investigation.
The investigation will also look at the impact of other issues on the image of the judiciary.
Driza, 37, told the court she found two intimate videos of Judge Khan - in one he was with Judge J and she was apparently snorting cocaine. Judge J strongly denied any suggestion she had taken drugs.
Driza, who is liable to eventually be deported back to Brazil, was also convicted of stealing intimate videos from Judge Khan.
Driza was acquitted of blackmailing Judge Khan but convicted of the same offence against Judge J.
There was great media interest in the case, with the court hearing how Judge J and Judge Khan had been lovers, with the latter eventually starting an affair with Driza.
Roselane Driza was working illegally in the UK
Neither judge - who are both employed by the Asylum and Immigration Tribunal - will be sitting while the inquiry is ongoing.
Judge Khan, who sits as a Recorder, will remain on full pay, while Judge J, on sick leave with stress for 18 months, will continue on the same pay. Neither has been suspended.
Officials conducting the investigation will speak to the judges and "relevant third parties", likely to include Driza and witnesses from her trial.
They will pass their findings to a nominated judge, who has not yet been named.
The judge will then advise the lord chancellor and lord chief justice whether the matter should be taken further.
Sanctions available following the investigation range from warnings and reprimands to removal from office in extreme circumstances.
A statement from the Department for Constitutional Affairs said: "The lord chancellor and the lord chief justice strongly believe that the public must have confidence in judges, and take seriously any allegations against them of misconduct...
"In particular the lord chancellor and lord chief justice are concerned about the allegation that Mr Khan and Ms J employed Miss Driza as a cleaner when she was ineligible to work in this country."
The statement added: "On a more general note, the lord chancellor and lord chief justice have great confidence in the professionalism and high standards of the judiciary as a whole and consider it unfortunate if these allegations are seen as calling this into question."