A wildcat walk-out among prison officers looks to have been avoided as union leaders and management prepare for talks at conciliation service Acas this week.

Officers at Saughton, in Edinburgh, and Barlinnie, in Glasgow, threatened to walk out today in a dispute over a pay offer.

The Scottish Prison Officers Association said they repudiated any strike action and warned members not to walk out or they could be sacked with no claim to unfair dismissal.

Letters were sent to each branch reminding officials of the agreed industrial relations policy and warning of the consequences of an unofficial walk-out by staff.

On Friday officers overwhelmingly turned down a pay offer of 2% and a 1.1% one-off payment.

In a ballot of the SPOA's 3000 members, 95% voted to reject the offer. Staff are angry that management would be in line to receive increases of between 5% and 31% in the proposed deal.

Staff at the two prisons had threatened a walk-out today, which would have left prisoners in jails with no warders and no-one to escort prisoners to court.

However, it is understood officers have pulled back from the walk-out threat, although contingency plans remain in place to ensure order is maintained in the prisons, which house some of Scotland's most dangerous prisoners.

A spokesman for the SPOA said: "We repudiate any strike action. The offer was rejected by 95% of members and we are now going to Acas on Tuesday."

Prison officers are banned by law from striking and the union could be taken to court if it was seen to sanction a walk-out.

A strike has occurred before. In 2001, a one-day walk out took place.

A spokesman for the Scottish Prison Service said: "Prisons have contingency plans to cover a range of eventualities. We will take action to minimise the effect should any action take place."

Meanwhile, prison bosses yesterday pledged to investigate claims that three jail warders posed for a racist photograph dressed as the Ku Klux Klan.

The Scottish News of the World reported that the pictures were taken at Glasgow's Barlinnie jail.

The Scottish Prison Service branded the alleged behaviour "unacceptable" and said it had asked for any evidence to be handed over.

However, prison chiefs rejected claims in the paper that racism is rife at the jail.

"I would say that the actions of a minority have very much undermined the very good work that takes place in prisons," a spokesman said.

"We will investigate any evidence provided by the News of the World. This type of behaviour is unacceptable and very disappointing."

The spokesman stressed that the SPS has been working closely with Racial Equality Councils in the West of Scotland and Edinburgh and the Lothians, in recognition of the multi-cultural diversity of prison populations and staff.