A district judge, a high-profile solicitor, and six court clerks were arrested yesterday and questioned over allegations of corruption and bribery.
David Tapp, the most senior magistrate on Merseyside, is expected to be suspended by the Lord Chancellor today, in response to a police inquiry into "grave and serious" allegations.
Mr Tapp was arrested yesterday, as was Kevin Dooley, a solicitor whose clients have included Liverpool Football Club, the footballer Robbie Fowler, and victims of the Hillsborough football disaster.
Mr Dooley is already under investigation by the Law Society, the solicitor's governing body, over allegations of fraud and schemes to launder money. His certificate to practice as a lawyer has been suspended and he is expected to face a disciplinary tribunal.
The criminal corruption inquiry is thought to be concentrating on allegations that Mr Dooley offered court officials inducements to provide him with preferential treatment.
Mr Dooley, aged 60, who was unavailable for comment yesterday, is expected to deny any allegations of wrongdoing.
The solicitor, who has also represented the footballers Stan Collymore and Graeme Souness, as well as the murdered toddler Jamie Bulger's father, Ralph, ran the successful law firm Dooley & Co, in Merseyside.
But in June last year, his offices in Liverpool and Kirkby were raided by officials from the Law Society's regulatory branch, the Office for the Supervision of Solicitors (OSS). A number of documents were seized, and Mr Dooley's client files were taken.
The OSS intervened because they believed Mr Dooley was "knowingly and dishonestly" involved in bank instrument frauds and possibly in money laundering.
The Law Society confirmed yesterday that the OSS would issue proceedings against Mr Dooley for him to appear before a disciplinary tribunal.
It was unclear if these fraud allegations were connected to the criminal inquiry.
Meanwhile, the Lord Chancellor, Lord Irvine of Lairg, has written to Mr Tapp, one of 98 district judges who work in magistrates' courts in England and Wales, and is expected to suspend him today until the police inquiry is completed.
Mr Tapp, who was appointed to his position in 1992 and works at Dale Street magistrates' court in Liverpool, is the first judge to have been arrested in the past five years.
The six clerks arrested were among 60 officials who manage magistrates' courts in Merseyside, controlling the order of cases and providing advice to lay magistrates and district judges.
Malcolm Marsh, the chief executive of Merseyside Magistrates Court Committee, said: "Any allegation of corruption is a grave and serious matter but particularly for our organisation as we have such an important part to play in the criminal justice system. We expect the highest integrity from staff and take these allegations very seriously." He added that there would be an internal investigation and said a contingency plan would be put into action in case staff were suspended.
There are a total of 40 magistrates' courts in seven courthouses across Merseyside, dealing with more than 90,000 defendants a year. Magistrates' courts in Merseyside were closed yesterday.
A statement by the Lord Chancellor said: "I take allegations of corruption and the impact they may have on public confidence very seriously."
