Stuart Murray, president of the Scottish Solicitors Bar Association, told MSPs at Holyrood that the third verdict is a “safety valve” for jurors.

The Scottish government is advancing legislation to abolish the verdict, bringing Scotland into line with other jurisdictions that have simply ‘guilty’ and ‘not guilty’ verdicts.

The Victims, Witnesses and Justice Reform (Scotland) Bill also proposes a pilot of juryless trials in rape and attempted rape cases. This proposal has been widely condemned by the legal profession and faces widespread opposition.

Mr Murray said that scrapping ‘not proven’ is “being considered at a time when other considerations are being looked at which could completely alter the landscape of the criminal justice system in Scotland”.

He added: “This seems to come at a time when along with those other proposals, it puts, I think, the criminal justice system in Scotland at risk of being adulterated and access to justice and the rights of the accused, innocent until proven guilty, at some substantial risk.”

His comments follow those of others who have warned that removing the verdict could lead to a rise in wrongful convictions.

Stuart Munro, of the Law Society of Scotland, told the committee that the present arrangements are “broadly safe”.

He said that “disturbing that balance will have ramifications”, adding: “If you take away something that is regarded as a safeguard, and don’t address some of these other areas of concern, then yes, there would have to be a risk of an increase in wrongful convictions.”

The bill would also reduce juror numbers from 15 to 12, with a majority of eight needed to secure a guilty verdict.

But Ronnie Renucci KC, vice-dean of Faculty, said: “That majority has to be 10, at least 10.”