Prison officers in England and Wales are reporting for work as normal after their first national strike was ended.
Officers at Bristol prison began to return to duties on Wednesday afternoon
All 129 non-private prisons suffered disruption on Wednesday after the surprise walkout by some 20,000 staff in a row over pay.
A High Court injunction was granted against the Prison Officers' Association (POA), and union leaders eventually called off the strike.
The government and the POA are due to hold fresh talks on Friday.
The POA said Justice Secretary Jack Straw had offered "full and meaningful" talks and that it hoped this was "not merely a stalling tactic".
Mr Straw said: "I am glad that the POA has issued this instruction to return to work."
A spokeswoman said Mr Straw had arranged to meet the union's leadership on Friday, before he knew about the strikes.
PRISON OFFICER SALARIES
Auxiliary staff: £13,318
Night patrol: £14,084
Entry officer min: £17,744
Prison officer: £27,530
Senior officer: £29.371
Principal officer: £31,913
Recommended top pay in posts Source: Office for Manpower Economics, April 2007
BBC home affairs correspondent Daniel Sandford said he thought many members of the POA felt they had "made their point" but that they had not won anything in terms of the negotiations.
POA chairman Colin Moses told BBC News he could not rule out further strike action.
"Those decisions will be made by my membership," he said. "What seems to have been forgotten here is that we balloted our membership.
"What we have been asking for specifically since April is for someone to talk to us about the disgraceful way we have been treated.
"For two years running [we have received] below inflation pay awards when we have 80,000 prisoners."
David Wilson, a former prison governor who is now professor of criminology at the University of Central England, told BBC Radio 4's Today that the strike had been "undoubtedly illegal" and "potentially very dangerous".
But he said it had successfully drawn public attention to the prison officers' situation and the conditions they work in.
"Since 1997, 25,000 more people have been put in jail but the prison officers' pay has not gone up accordingly," he said.
"The Prison Officers' Association have a voice. I despair of prison governors actually saying anything about the current overcrowding."
Prison officers and their dogs on strike at Wormwood Scrubs, London
The strike action came after the union pulled out of a no-strike agreement with government.
The POA said the government had failed to deliver on "promise after promise" and it decided to call the strike without prior warning to avoid attracting a court order.
An independent pay review body for prisons has recommended a 2.5% salary increase but the 28,000-member POA said the value of the rise is reduced to below inflation by being introduced in two stages.
POA general secretary Brian Caton said: "After a day of what we describe as somewhat traumatic times in the history of the union, we will lead our membership back to work and we will do that in an orderly fashion and that is regardless of any court injunction."
Meanwhile, Prime Minister Gordon Brown, speaking on Thursday morning, said inflation had been tackled over the past 10 years through "discipline in pay awards".
"The staging of pay awards is a crucial part of the fight against inflation," he said.
Visitors turned away
The government, which described the strike as illegal and unjustified, has denied it failed to address concerns about pay and falling morale among prison staff.
During Wednesday's strike, prisoners were kept locked in their cells, senior managers took charge of duties such as distributing meals and visitors were turned away.
Among the prisons affected were:
The Association of Chief Police Officers said police cells were used for about 900 inmates who could not return to their normal prison after court appearances and for those newly sentenced.
- Liverpool, where 25 to 30 striking officers temporarily suspended their action to deal with three inmates who had climbed on to a roof
- Birmingham where fire engines attended to deal with two minor blazes
- Frankland high-security prison, County Durham, where a handful of striking officers volunteered to go back to work because of the danger posed by inmates
- Wormwood Scrubs, Manchester, Cardiff, Dartmoor, Exeter and Wakefield, where POA officials claimed 745 inmates - including Soham killer Ian Huntley - were guarded by no more than 20 senior managers
Granting the injunction, High Court judge Mr Justice Ramsey said there was an "overwhelming case" that a legally binding agreement had been broken.
Mr Justice Ramsey said any strike would have "particularly difficult consequences" for prisons already filled to capacity.
The prison population in England and Wales is close to capacity levels, with about 80,000 people currently held.