RUTH Davidson’s plans to give Scotland’s judges the power to lock up violent criminals and throw away the key, unravelled yesterday, with top lawyers and legal experts calling the measure completely unnecessary.

The Scottish Tory leader used First Minister’s Questions to say her party would bring forward a bill to introduce “whole-life sentences,” that would leave the country’s most violent criminals in prison without the chance to apply for parole.

But Scottish judges already effectively have the ability do just that.

Davidson made the pledge as she quizzed Nicola Sturgeon on the sentence given to the killer of 15-year-old Paige Docherty.

John Leathem was given a man- datory life sentence, which included a punishment part of 27 years for his frenzied murder of the Clydebank teenager last March.

Last week, the delicatessen owner had his tariff cut by four years at the Appeal Court in Edinburgh.

Davidson said: “As it stands, our judges do not have the tool of a whole-life tariff at their disposal and we say that we should.

“We can sit in this Parliament and we can wring our hands and we can express outrage every time something like this happens, or we can do something about it. I want to do something about it.”

Davidson pledged: “If the Scottish Government won’t act, then I can say the Scottish Conservatives will do so by pushing ahead with a member’s bill making the case for the introduction of whole-life sentencing in Scotland.

“We need to stand up for families who see sentences for murder cut less than a year after they have been handed down and we should change the law so that families like Paige Doherty’s feel that the law is tipping back in their favour and that the worst criminals are kept off our streets forever.”

The First Minister said she would look at the proposal: “My heart breaks for the family of Paige Doherty.

“I met Paige’s mother last year and there literally are no words to express the pain and grief that she and the rest of her family have gone through.”

Sturgeon said she had “no difficulty”

understanding comments made by the Justice for Paige campaign group, who branded the reduction in Leathem’s sentence “heartbreaking”, arguing that it “serves no justice to Paige and her family”.

Sturgeon added: “If I had been a relative of Paige Doherty, I would have felt exactly the same.”

“As well as being First Minister, I’m also a human being and there are many occasions when I look at decisions of courts and wish that different decisions had been reached. It may well be this is one such case.”

The First Minister went on: “No matter what framework and context parliament sets on any of these issues, we will still have instances where decisions by courts are decisions that many people feel are the wrong decisions. That’s in the very nature of an independent judiciary.

“But I am very clear that where there is evidence the law has to be changed or action has to be taken, then that is something this Government and this Parliament should reflect on very seriously.”

John Scott QC, the convenor of the Howard League for Penal Reform in Scotland, said the bill proposed by Davidson “would be entirely un- necessary in Scotland”. “There isn’t anything to stop a sentence which would in effect be a whole-life sentence from being imposed,” he said.

In Scotland, judges handing down a life sentence must set a minimum term after which the prisoner will be eligible to apply for parole. In some cases, violent killers are given punishment parts which will likely exceed their life expectancy.

In 2014, Angus Sinclair, 69, the killer in the World’s End murders, was given a sentence with a punishment part of 37 years when he was finally convicted for the murders of Christine Eadie and Helen Scott.

“It’s not impossible that he might live beyond that,” Scott said, “but it wouldn’t mean he would get out either.”

Being eligible for parole doesn’t mean automatically being released, and boards assessing prisoners must consider public safety. Of the 351 life prisoners assessed by the Parole Board in 2013-14, 56 were directed for release.

Scott added: “The courts have to deal with a variety of individual circumstances and take them into account as best they can, while recognising this is about the part of the sentence which is just for punishment and retribution as the other part of what’s involved in dealing with someone for murder and dealt with by the parole board, but only after the tariff has expired.”

Professor Fergus McNeill, from the Scottish Centre for Crime and Justice Research, said: “While I understand why politicians feel the need to respond to public sentiment about tragic and troubling cases, I find it worrisome when they second-guess judicial decisions.

“Politicians have not sat through trials and appeals and are not in possession of all of the facts. That’s why I won’t offer an opinion on the merits of any particular case. Perhaps doing so makes for an easy way to curry public favour — but it’s a poor way to lead public debate on responsible and fair approaches to punishment.”