Holyrood has inflicted more damage to Scots law since devolution than Westminster did in 300 years, a leading lawyer has claimed.

Alistair Bonnington, a solicitor advocate, said "huge damage" had been done since the Scottish Parliament was established in 1999.

In a wide-ranging attack, he hit out at the ending of double jeopardy - a centuries-old tradition which prevented a person being tried twice for the same crime - as well as accusing MSPs of conducting a "sustained campaign" to erode legal aid.

Mr Bonnington, a former honorary professor of law at Glasgow University, also said he feared two "gold standards" of Scots law would soon be lost - the need for evidence to be backed up with corroboration and the ban on juries being told about an accused person's previous convictions.

A review of the law by Lord Carloway has already recommended doing away with the requirement for corroboration - with this having being accepted by the Scottish Government.

Ministers are currently consulting on how best to implement Lord Carloway's recommendations.

Meanwhile, the Scottish Law Commission has called for both juries and judges to be told if an accused person has previous convictions - something ministers are now considering.

Mr Bonnington said: "Sadly it is not going too far to say that Holyrood has done more harm to Scots law than Westminster managed in more than 300 years."

He hit out at the "sustained campaign by MSPs to erode legal aid to the point where lawyers will refuse to represent the impecunious accused in criminal cases".

The lawyer added: "Few legal firms now do legal aid work because if they did they would go bankrupt."

He also claimed the "established traditions of Scots law have been abandoned to fit in with right-wing tabloid thinking".

Mr Bonnington argued Scotland now had "Soviet-style laws on double jeopardy", claiming the ban on trying someone for the same case twice had been ended in a bid to retry the World's End murder case after Angus Sinclair was cleared of killing Helen Scott and Christine Eadie in Edinburgh.

The lawyer went on: "These retrograde steps seem sure to be followed by the destruction of two of the gold standards of Scots criminal law: the need for corroboration of evidence and the prohibition against juries knowing prior convictions.

"Again, these are the kind of rules one expects to find in the third world."

He added: "Scots lawyers are having to defend Scots law against our own Parliament. It clearly is not safe in their hands."

Mr Bonnington told BBC Radio Scotland that the country had a "legal aid system which is collapsing".

The lawyer said: "I last did a criminal trial in 1992. If I did one tomorrow, I would be paid less than the last one I did in 1992. You can't run a system like that."

He added: "If you read the Scottish legislation, a lot of it looks as if it's been written by a primary school child. It really is embarrassing.

"I've had to go to conferences all over the world. You try and be proud of your system, but that is becoming increasingly difficult to do."

A Scottish Government spokeswoman said that reform of the law "must be properly considered and researched".

She stated: "Reform of the law on double jeopardy followed a detailed assessment by the independent Scottish Law Commission and a Government consultation exercise.

"The principle against multiple trials has not been abolished.

"As in England and Wales and other jurisdictions, a limited exception has been created to allow a new trial only where new evidence with a significant impact emerges following the first trial.

"The proposed abolition of the requirement for corroboration was recommended in an independent review by Lord Carloway.

"Lord Carloway's recommendations are currently subject to a Government consultation exercise, which closes on October 5.

"The consultation specifically seeks views on whether any additional safeguards would be required as a result of removing the corroboration rule."

She also said: "We provide substantial levels of funding to ensure that legal advice and representation is available to people who could not otherwise afford it.

"Last year the Scottish Legal Aid Board reported an increase in the number of firms doing legal aid work and we will continue to provide fair and affordable remuneration for solicitors to ensure continued provision of this important service."