One prisoner has already been awarded compensation

Cathy Jamieson expressed her anger at the blunder, which could cost millions.

The Scottish Executive ran out of time to appeal against a court ruling that slopping out in jails amounted to degrading treatment.

She said the error appeared to have occurred in offices which came under the auspices of Lord Advocate Colin Boyd.

Ministers are going back to court to ask for more time to appeal against a judge's ruling that cells without toilets breach the human rights of inmates.

The executive has admitted an "administrative error" led to a mix-up over a deadline for appealing against the ruling.

We must not forget that this was an entirely avoidable fiasco Annabel Goldie Tory justice spokeswoman

Papers should have been lodged within 21 days of the legal judgement.

A spokesperson said: "The executive legal team have already initiated urgent remedial action."

It is expected the executive will be told on Tuesday whether it will be given more time to lodge an appeal against the ruling.

Ms Jamieson said that "furious" was only a mild description of her feelings over the error.

She said: "Something went wrong here, we need to get to the bottom of that, but more importantly, as soon as this was discovered, measures were taken to try and rectify the situation."

She added: "It was very clear the ministers intended to appeal this and it was very clear that the decision was taken in perfectly adequate time for the appeal to be lodged.

"The investigation needs to find out what happened. We'll know that soon."

'Gross ineptitude'

Scottish National Party justice spokeswoman Nicola Sturgeon said Ms Jamieson was now at the mercy of a judge's discretion.

She said: "A judge may decide that the Scottish Executive can have more time, but equally the judge may decide that it cannot.

"In those circumstances the Scottish taxpayer is going to have a hefty bill to foot because many more prisoners will come forward and make similar claims."

Ms Sturgeon said that the minister should be paying more attention to detail.

She added: "In a stunning display of political cynicism, she is desperately trying to point the finger elsewhere to save her own skin."

Armed robber Napier was held in Barlinnie Jail

Scottish Conservative justice spokeswoman Annabel Goldie accused the executive of "gross ineptitude" and of having a "devil-may-care attitude" to taxpayers' money.

She said: "Money will now be paid to convicted criminals rather than being spent on putting more police onto our streets or improving our public services.

"We must not forget that this was an entirely avoidable fiasco."

The slopping out decision, made in the Court of Session in April, could cost the Scottish Executive millions of pounds in compensation.

The court awarded armed robber Robert Napier more than �2,000 in compensation and claims from other inmates could follow.

Ms Jamieson insisted at the time there were grounds to challenge Lord's Bonomy's judgement.

Napier raised a legal challenge in 2001 under the European Convention on Human Rights.

'Degrading treatment'

He was held at Barlinnie Jail after being arrested for failing to appear at the High Court on robbery, assault and abduction charges.

Lord Bonomy awarded him �2,400 after ruling that slopping out amounted to degrading treatment.

He said the practice violated articles three and eight of the convention and the common law "duty of care."