Prisons are no longer places for punishment, ministers have said after the phrase was excluded from the first legal definition of the purpose of jails.
A new Prison and Courts Bill, proposed by Liz Truss, the Justice Secretary, tells prison governors they must protect the public, reform and rehabilitate offenders, prepare prisoners for life outside and be safe and secure.
The legislation does not place any obligation on prisons to punish offenders, reigniting the row over so-called “holiday camp” jails.
Critics suggested Ms Truss had “gone soft on crime”, but the Ministry of Justice insisted that the courts punished offenders by sending them to prison, and that no further punishment was necessary once they were locked up.
The news comes in the week that Scotland Yard warned that Britain is experiencing a surge in violent crime and the prisons inspector found that guards have “all but lost control” at a crisis-hit jail where inmates are allowed to wander around in their dressing gowns.
In recent months Britain’s jails have experienced some of the worst rioting in decades, and pictures have emerged showing inmates with drugs and alcohol in their cells and even frying steaks.
Prisoners are also entitled to have televisions and games consoles in their cells as a reward for good behaviour, and tens of thousands of mobile phones are smuggled into prisons every year.
It has also emerged that violent crime rose in all but one of the police force areas in England and Wales last year.
Figures published by the Office for National Statistics showed that in some areas, violent crime such as assaults almost doubled over the course of 12 months.
Nottinghamshire was the only police force area that recorded a fall in violent crime.
Paul Nuttall, the Ukip leader, said the mission statement for prisons contained in the proposed new legislation “beggars belief” because punishing offenders is an “absolute bedrock” of the prison system.
He said: “It suggests Liz Truss has had the wool pulled over her eyes by so-called 'progressive' penal policy pressure groups.
"Voters will be forgiven for wondering whether the Conservatives have simply gone soft on crime.
“By not specifically referencing punishment it could allow governors further to soften regimes in prisons so that they become more like holiday camps rather than serious corrective institutions.”
Ms Truss is already under mounting pressure with Cabinet colleagues calling for her to be stripped of her role as Lord Chancellor and for her department to be broken up.
The Conservative MP Philip Davies said he would table an amendment to the Bill, which is due to be debated by MPs in its committee stage next week, to insert the word punishment in the mission statement for prisons.
He said: “The purpose of prisons first and foremost should be punishment. The Government should recognise that. All these liberal Lefties think that people having their freedom taken away is a punishment in itself.
“But to many people it is not. All these prisons inspectors come from their seven bedroom mansions and say ‘oh it is pretty dreadful in here’.”
The House of Commons library, which carries out research for MPs, suggested the wording of the Bill reflects the view the offenders "come to prison as punishment and not for punishment".
Ms Truss said earlier this year: "The Prisons and Courts Bill is clear that prisons are there to deliver the sentences of the court – depriving people of their liberty to punish them for their crimes.
“This reflects and underlines the existing principles set out in the Criminal Justice Act 2003, which states that one of the purposes of sentencing is the punishment of offenders."
When the new Bill becomes law it will augment the 2003 Act, which defined the purpose of sentencing, but not of jails. It said sentencing was for punishment, the reduction of crime, rehabilitation, protecting the public and making reparation to people affected by their offences.
The Bill says that prisons must protect the public, reform and rehabilitate offenders, prepare prisoners for life outside and be safe and secure, but not punish them.
Ms Truss wants to bring down reoffending - which costs the economy £15 billion per year - by ensuring that prisons educate inmates and teach them skills that will enable them to get jobs once they are released.
A Ministry of Justice spokesman said: “Legislation is already explicit that the purpose of a prison sentence is punishment by the deprivation of liberty.
“What the Bill is about is making sure prisons are places of discipline, self-improvement and hard work.
"This includes getting offenders into training and jobs when they leave prison so crime and misery to society is reduced."