The latest deadline for the investigation is December 18.

Rape Crisis Scotland chief executive Sandy Brindley said the Faculty was a “boys’ club” that was “closing ranks” to “protect one of their own”.

She told the Daily Record: “Jackson is being allowed to pull the strings in his own investigation, fobbing it off until he is able to retire in peace.”

Mr Jackson was filmed discussing the case on a train, identifying two of his clients’ accusers, who enjoy anonymity. He later stepped down as Dean of Faculty.

Ms Brindley said: “It’s hard to see this latest move by the Faculty as anything other than a boy’s club closing ranks to protect one of their own.

“You’d be forgiven for thinking that Jackson is being allowed to pull the strings in his own investigation, fobbing it off until he is able to retire in peace. This is unacceptable and in our view undermines public confidence in the Faculty of Advocates.”

Mr Jackson, however, said: “It wouldn’t help me in any way delaying it. But those who act for me, my legal people, they have been carrying out certain investigations and will no doubt be dealing with it as timeously as they possibly can.

“I have got no motive to delay it unduly. I am not retiring in the foreseeable future. So that motive, I can tell you, has absolutely got no merit.”

A spokesperson for the Faculty said: “Mr Jackson is the subject of a complaint which is being addressed under the Faculty’s Discipline Rules.

“His lawyers sought the latest extension in order to be able to finalise his defence. That extension was granted in the interests of fairness.”