Mr Ronald said there would be "kudos" attached to the painting's return
A solicitor facing extortion charges has told a court that claims he was holding a da Vinci painting to ransom were "arrant nonsense".
Marshall Ronald, 53, admitted he hoped to get a financial reward and "kudos" for the return of the stolen artwork.
He claimed it was a commercial deal but that he was also acting "with passion".
Mr Ronald and four others deny trying to extort £4.25m for the return of the Madonna of the Yarnwinder. They are not accused of stealing the painting.
The trial at the High Court in Edinburgh has now entered its fifth week.
Mr Ronald described an approach to his small law firm in Lancashire by two Merseyside private investigators Robert Graham, 57, and John Doyle, 61, who are among his co-accused.
The duo had a company called Stolen Stuff Reunited which specialised in returning stolen goods - particularly items of sentimental importance but of little value to thieves.
He said the pair had heard there was a chance they could return the painting to its owner and wanted advice on whether it could be done lawfully.
Defence QC Donald Findlay asked him what he expected to receive for returning the work.
"At that time it was 20% of the overage but the other promise that was relevant to myself, Jack Doyle and Robbie Graham was that there would be a tremendous amount of kudos," said Mr Ronald.
He suggested that returning it would be like the return of Edvard Munch's The Scream.
"The kudos would be substantial," he said.
Mr Findlay said it would be "pretty good publicity" for a one-man law firm.
"Yes, there was always the option that later on I could do something with that," Mr Ronald said.
However, he denied that a meeting in a Glasgow law offices in July 2007 had been a meeting of conspirators.
Mr Findlay said: "You sat down and discussed extorting money out of somebody by ransoming the painting in some way or another."
"Arrant nonsense," Mr Ronald replied.
He said the meeting had been to discuss the logistics of returning the painting.
He agreed that the amount of money on offer was an issue but insisted that giving the Buccleuch family back its painting was not just a "side issue".
"We did this with a passion," he said.
"We returned this painting with a passion."
On trial along with Mr Ronald, 53, are Mr Graham and Mr Doyle, all from Lancashire, Calum Jones, 45, from Renfrewshire, and David Boyce, 63, from Lanarkshire.
They deny conspiring to extort £4.25m and an alternative charge of attempting to extort the money.
The trial continues.