Tougher restrictions on the use of home detention curfews (HDC) have resulted in a significant drop in the number or prisoners being freed from jail on electronic tags.

Scottish Prison Service (SPS) chief executive Colin McConnell said since the presumption against the granting of HDC for those convicted of violent crimes has been brought in, the number of prisoners freed on these terms has gone from 25 to 30 a week to just seven.

Justice Secretary Humza Yousaf announced the new measures last month in the wake of the murder of father-of-three Craig McClelland from Paisley.

He was stabbed to death in July 2017 by James Wright, who was “unlawfully at large” while on home detention curfew.

HDC have been used in Scotland since 2006 and allow for prisoners to serve part of their sentence in the community while being monitored via an electronic tag.

Craig McLelland, whose killer was ‘unlawfully at large’ while electronically tagged (Police Scotland/PA)

The new presumption against HDC for those serving a sentence for a violent crime, or one involving the use of a blade or another weapon, has brought about a “sea change in the level of grant of HDC”, Mr McConnell told MSPs on Holyrood’s Justice Committee.

Overall, he said: “There’s been a couple of horrendous experiences with people in the community who have either been on HDC or on licence and that has caused us collectively to reflect on that, which has led us to the position we are in now.”

Following the introduction of the new guidelines, which also include a presumption against releasing an offender on HDC if they are on the sex offenders register or have been linked to serious, organised crime, he said his instruction to prison governors has been “that we should be very, very careful in terms of how we arrive at those decisions to grant HDC”.

Mr McConnell said that was in part due to “the level of political and public concern that there has been quite recently in terms of people being released into the community”.

He said: “In terms of the situation now, there is a considerable restriction and presumption against the grant of HDC, which have resulted in since these new measures were introduced approaching a 75% reduction in the grant of HDC.

“Where at one time we may have been somewhere between 25 and 30 grants of HDC per week, we are now down to seven.”

The SPS boss added: “Previously the presumption would have been unless there were particular factors, the anticipation would have been to grant an HDC, so that has completely been turned around, the presumption is not now to grant HDC where there are any concerns at all.”

Mr McConnell told MSPs  he did not know how many crimes had been committed by prisoners who were out on HDC.

But he said he would be “shocked and stunned” if the suggestion by Labour MSP Daniel Johnson that 16 murders have been committed by prisoners who have been released on a tag was correct

The Labour justice spokesman said: “The numbers that have been intimated to me are 16 murders and dozens of serious sexual assaults. Would those numbers surprise you?”

Mr McConnell said he would be “entirely unfamiliar with those numbers” as he told the committee his staff were currently checking the statistics on how many crimes had been committed.

His view was backed by Chief Superintendent Garry McEwan, of Police Scotland.

He said: “I have to say I would be very surprised if there were 16 murders since 2006 with those that have been out of home detention curfew.

“I would be extremely surprised if that was accurate but I would be interested to get the figures.”

Wendy Sinclair-Gieben, HM Chief Inspector of Prisons for Scotland, raised concerns that a tougher stance on the use of HDC could have “unexpected consequences” for prisons and their staff.

She said: “I had real concerns before this review started that there might be unintended consequences of a rise in the prison population, and not just from HDC.

“My concern is if we become risk averse on HDC, we will also become risk averse on parole, people going to the open estate, which means the pressure on the prisons, some of which are already struggling, is going to become huge.

“The pressure on the population also puts pressure on the staff and also puts pressure on all sorts of other things, the level of self harm goes, the level of violence can go up.”

She added: “I think we need a further review in a further three or five years which says have we got this right, is this having the consequences we wanted for HDC. We need to do that proper evaluation.”