LYNDA SPENCE was abducted, tortured and murdered as part of a plan involving "unspeakable cruelty, pain and humiliation", a court has heard.

The businesswoman experienced days of captivity, taped to a chair in an attic room, solicitor general Lesley Thomson told a jury.

The plan was motivated by money and loss of face, and resulted in "extremes of violence", the High Court in Glasgow heard.

Ms Thomson said Colin Coats was the controlling mind behind the plan, helped by his right-hand man Philip Wade.

The solicitor general was speaking as she began summing up the case for the prosecution, following weeks of evidence at the court.

Coats and Wade, both 42, are on trial charged with abducting the 27-year-old financial adviser in April 2011, torturing and murdering her. They deny the charges against them.

Two former co- accused, David Parker, 38, and Paul Smith, 47, were cleared of Ms Spence's murder after pleading guilty to a reduced charge of holding her against her will and assaulting her.

In her opening remarks, Ms Thomson told the jury: "The Crown case is that four men controlled the last two weeks of Lynda's life.

"The evidence points to the man in command being Colin Coats. He had his right-hand man, his close friend, his 'brother from another mother', Philip Wade.

"The two supporting members of the team, David Parker and Paul Smith, have accepted their part. They provided the place of captivity. They guarded Lynda day after day while she was tortured by Colin Coats and Philip Wade.

"Did they become increasingly scared of what they had gotten into, all under the leadership of Colin Coats?

"There was no such fear on the part of Philip Wade or Colin Coats. They continued to act together to end Lynda's life, and beyond, to cover up anything that might connect them to it."

The court has heard various "dramatic suggestions" during the trial but they did not play any part in Ms Spence's death, Ms Thomson said.

"The truth, sadly, is more sordid and closer to home. The truth is to be found in a flat in a residential street, in Meadowfoot Road in West Kilbride.

"The Crown case is that the motivation was money, driven by greed, fuelled by loss of face; all resulting in anger, a terrible anger that went to extremes of violence, barbaric in its execution and culminating in Lynda's death."

Ms Thomson said that, although no body has been found, the jury could conclude that Ms Spence was dead.

"This is a young woman who no official checks can find a trace of," the prosecutor said.

Earlier, the court heard of four possible sightings of Ms Spence.

The trial before Lord Pentland continues.