Reliance has been put on notice over its performance

Cathy Jamieson received the deadline from Information Commissioner Kevin Dunion, who intervened after being contacted by the Nationalists.

Reliance took over responsibility for Scotland's prison escort service at the beginning of April.

But since then the company has come under fire following a series of high profile errors.

Commercial confidentiality

As a result, the roll-out of Reliance's contract across Scotland is currently on hold.

A spate of mistaken releases of prisoners in Strathclyde prompted Ms Jamieson to suspend the roll-out of the Reliance contract and she publicly told the company to "shape up or ship out".

In a statement to the Scottish Parliament on 21 April, Ms Jamieson said the contract between Reliance Custodial Services and the Scottish Prison Service (SPS) would be published.

However, she said this could only happen after agreeing which parts are kept secret for reasons of safety and commercial confidentiality.

Mr Dunion has now said Ms Jamieson must disclose the information by 21 May.

The growing suspicion is that she is desperate to avoid publication of the contract because she knows she cannot avoid responsibility for what it says. Nicola Sturgeon

After that date, the commissioner could use his new freedom of information powers to demand sight of the full contract and investigate the matter.

Mr Dunion made the ruling under the code of practice for access to executive information, which usually requires disclosure of information within 20 days of a formal written request.

Scottish National Party justice spokeswoman Nicola Sturgeon accused Ms Jamieson of deliberately stalling publication of the contract due to fears it would prove "the final chapter in her ministerial career".

Public domain

She said: "She signed off on this privatisation and now has to tell us how much profit Reliance are taking, and what penalties they face for their repeated mistakes.

"The growing suspicion is that she is desperate to avoid publication of the contract because she knows she cannot avoid responsibility for what it says."

Tory justice spokeswoman Annabel Goldie said that Ms Jamieson had been "at best semi-detached and at worst totally remote" from the contract.

"She has never been able to comment coherently about it and the government shouldn't have to rely on this ruling before they put it in the public domain," Miss Goldie added.

An executive spokesman said the contract was being prepared for publication.