A sheriff was asked to step down from a criminal trial because her love of birds presented a conflict of interest, the Lord President has revealed.

Another was asked to leave a civil case because a report presented in evidence was written by his colleague's wife.

Lord Gill has presented a list of voluntary or requested "recusals" from trials to Holyrood's Public Petitions Committee in response to a petition to create a mandatory register of interests for judges.

They include several cases where the judge or sheriff personally knew the accused, the pursuer, a witness or had some other connection.

Sheriff Annella Cowan was asked by the defence to recuse herself from a criminal trial in Aberdeen involving an investigation by the Royal Society for the Protection of Birds (RSPB) in October when she disclosed that she is a member of the RSPB.

Sheriff Martin Edington was asked to recuse himself by the defenders in a civil trial in Livingston when he disclosed that a report was written by the wife of one of the other resident sheriffs at his court.

The Lord President personally recused himself from a civil trial at the Court of Session in June because a relative was acting for the respondent.

There is no record of any judge or sheriff having to recuse themselves because a third party revealed a conflict of interest that had not been disclosed, he said.

Lord Gill presented the list to support his view that a register is not necessary because the judicial oath, the statement of principles of judicial ethics and the Judiciary and Courts (Scotland) Act already provide sufficient safeguards.

But petitioner Peter Cherbi said the list supports his call for a register, insisting "it is difficult to independently verify if members of the judiciary are properly recusing themselves when any instances of conflict of interest arise".

"If a register existed there is significant potential for the speeding-up of court hearings as litigants, legal teams, prosecutors and accused persons would already be aware of the judiciary's interests and could raise matters in advance, thus saving court time," he said.

"Additionally, if the judge was aware their interests were in the public domain, a published register would act as an additional encouragement for the judge to step down or ensure another judge hears the case, thus saving court time and preventing unnecessary delays and adjournments, both in civil and criminal proceedings.

"There have already been cases reported in the media where senior judges with shareholdings in major supermarkets did not recuse themselves from cases because current rules allow this.

"While some of these incidents pre-date Lord Gill's publication of recusals, the fact such an instance has occurred in the past with - apparently no record, proves the need for a register of judicial interests for all members of the judiciary to ensure the public themselves have access to such information on the judiciary."

Lord Gill has declined two invitations to give oral evidence to the committee but has provided a number of written submissions.

His reticence provoked a backlash from Conservative deputy leader Jackson Carlaw, who shares Lord Gill's scepticism of a register but said his refusal to appear demonstrates "an Edwardian establishment disdain of the right of the hoi polloi, as he sees it, to have any understanding of these matters".

New legal affairs minister Paul Wheelhouse will give his own view on the petition at the committee tomorrow.

His predecessor Roseanna Cunningham was not persuaded by the need for a register, insisting "the safeguards currently in place are sufficient to ensure the impartiality of the judiciary".

Mr Wheelhouse will be quizzed by, among others, former justice secretary Kenny MacAskill who was appointed to the Public Petitions Committee after being sent to the backbenches in First Minister Nicola Sturgeon's first cabinet reshuffle.