JUSTICE Secretary Michael Matheson is under growing pressure to end jail sentences of less than a year after the LibDems backed the chief inspector of prisons over the move.

Scottish LibDem leader Willie Rennie said his MSPs would vote in favour of such a plan if the SNP brought it to Holyrood, meaning there would be a majority in parliament for change.

There has been a presumption since 2010 that courts do not impose custodial sentences of less than three months so alternatives can be offered in a bid to reduce reoffending.

David Strang, HM Chief Inspector of Prisons for Scotland, called at the weekend for a new presumption against jail sentences of less than 12 months.

He told the BBC too many people were being sent to prison for short sentences, with more than half of those jailed for under a year reconvicted within 12 months.

Calling for more fines and community payback orders, he said: “The evidence is very clear that if you want to reduce crime then you don’t send people to prison for a short time.”

Mr Rennie said penal reform was “long overdue” in Scotland and said it was time that Mr Matheson "pulled the plug on damaging short stints in prison".

He said: “The Scottish Government launched a consultation over a year ago to explore options to strengthen the presumption against short-term sentences and despite bodies such as HMIPS supporting the end to the practice, the SNP are sitting on their hands."

LibDem justice spokesman Liam McArthur added: "Short-term sentences are incredibly destructive. All the evidence shows that community-based justice programmes and diversion-from-prosecution projects are far more successful in reducing reoffending and healing communities than short stints in prison.

"We don't need the support of the reactionary Conservatives or the muddled Labour Party to get this through. The Liberal Democrats will step up to vote this into law."

The Scottish Greens also support the end of prison sentences of less than a year, meaning a government-backed change could attract the support of 74 of Holyrood’s 129 MSPs.

John Finnie MSP, the Scottish Greens’ justice spokesperson, said: “In many situations, custodial sentences should only be used for those who pose a threat to the public.

“Green MSPs will be campaigning for short prison sentences of less than twelve months to be abolished and for a greater consideration of non-custodial alternatives such as robust rehabilitation programmes.”

However the Tories said the idea of ending such short sentences was “ludicrous”.

Justice spokesman Liam Kerr said: “We cannot fetter judges' discretion without full consideration of the consequences and wider policy context.

“There are many offences and circumstances where a custodial sentence of up to twelve months could be an appropriate punishment, and we need to allow judges the choice to hand down such sentences if they deem it necessary.”

The SNP government said it was mulling its options after a consultation on sentencing, and it was “only right” that it took time to consider the views of those who responded.

A spokeswoman said: "Our recent vision paper makes clear Scotland’s prison population remains unacceptably high. The associated plan sets out a range of actions we are taking to provide alternatives to ineffective short-term prison sentences and to prevent re-offending.

“We’ll continue to discuss how best to take this forward with the relevant stakeholders. There will, however, always be some crimes where a custodial sentence is absolutely justified.”