LUCY ADAMS and DOUGLAS FRASER

A heated debate is expected today in parliament about the Scottish Government's plans to extend the numbers of prisoners released early with electronic tags.

Kenny MacAskill, the Justice Secretary, yesterday laid out the reasons for extending the Home Detention Curfew (HDC) scheme, which currently allows short-term, low-risk prisoners to be released up to 135 days early with a tag.

The minister spoke about the overcrowding crisis as he visited Addiewell prison in West Lothian, a private facility nearing completion. He also hinted at "other options" to ease the prison population.

His comments came after the governor of Barlinnie Prison warned that prisons are being treated solely as a place for warehousing people, rather than for rehabilitation.

Bill McKinlay said that Barlinnie is close to crisis levels and that it would cease to function properly if its population, currently around 1500, reaches 1665.

The Justice Committee will today debate whether the scheme should be extended to longer-term prisoners and lengthened from four-and-a-half to six months.

However, Labour and the Tories are not expected to back the changes without some significant modifications.

They are expected to argue that at the very least the measure should be restricted and only run for the next 10 months - until the new prison at Addiewell opens.

Mr MacAskill hopes to persuade MSPs on the Justice Committee to sanction a widening of the curfew scheme.

But last night Pauline McNeill, Labour's justice spokeswoman, said: "It is very unlikely we would let this through as it stands. We are not against this in principle but it is about who is it available to, the risk assessment of these people, and how early they are allowed out."

Meanwhile, more than £47,000 of public money is being spent on staffing and membership fees for the Scottish Prison Service to be part of an international association with close connections to the private sector.

Ministers have asked the prison service to review its membership of the International Corrections and Prisons Association (ICPA), following concerns raised by SNP MSP John Wilson that it is not appropriate for an SNP administration to be aligned to this organisation.

The prison service is paying some £45,000 for a member of staff to be seconded to the organisation and some £2600 in membership fees.