More than 1,000 prison officers are believed to be involved in corruption, according to a leaked report into the Prison Service.
The damaging report, which is the result of an investigation more than a year long, concludes that while most staff operate in an honest way, a significant number of officers are involved in corrupt practices.
The report, which was leaked to the BBC, claims corruption ranges from bringing mobile phones and drugs into the jail to accepting cash payments from inmates for transfers to less secure prisons.
Mark Leech, editor of The Prisons Handbook, the annual guide to the penal system in England and Wales, said the report revealed that the service was "institutionally corrupt".
The report is the result of an inquiry by the Metropolitan Police.
It states that corruption often starts with "inappropriate relationships" between prisoners and staff and that there are currently nearly 600 such relationships.
As part of the inquiry, police visited senior Prison Service officials including area managers and governors.
The inquiry also looked at the Prison Service intelligence database, known as "Watson".
One of the most damaging claims contained in the report was that when intelligence is received about corrupt officers, often no action is taken to tackle it.
One Prison Service area manager is quoted as saying that 70 Security Intelligence Reports filed by officers identifying colleagues as corrupt had never been referred to headquarters and no action was taken against them as a result.
Mr Leech said: "This report reveals that what was claimed to be a few isolated cases of corruption is in fact the tip of a huge iceberg of dishonest practices that has infected the Prison Service nationwide.
"In short, it stands accused of being institutionally corrupt right across the country.
"The report shows that what the Prison Service currently has in place to tackle corruption is woefully short of what is actually needed in order to root out those officers who pose a threat to their colleagues, a danger to the public, and who bring shame on the service as a whole."
One unnamed prison boss is quoted in the report as saying: "Here corruption is endemic... I've identified over 20 corrupt staff, but there may be more."
Another says: "I currently have 10 corrupt staff and I am managing the threat they pose to my prison - positive mandatory drug testing figures are over 20 per cent so it must be staff bringing in drugs."
Brian Caton, general secretary of the Prison Officers' Association, said there were approximately 19,000 prison officers currently working in England and Wales.
He said: "The most irresponsible thing I find in this is that the Prison Service seem to understand that there is this amount of corrupt prison officers and are prepared to do not much about it. I find that absolutely irresponsible and unforgivable."
Mr Caton blamed the high level of corruption within the ranks of Prison Service officers on poor pay and an inadequate recruitment process.
He said: "There will always be a problem as long as prison officers are as poorly paid as they are and as long as the Prison Service vetting process and recruitment process are not fit for purpose."
He said potential employees are no longer interviewed but have to go through a series of role plays.
Mr Caton acknowledged that his organisation had a part to play in tackling corruption.
"If we find out that someone is corrupt, if the Prison Service did nothing about it, this union would go to the police station and tell the police this person was corrupt.
"We have no time for people being corrupt in the Prison Service, it's absolutely irresponsible.
"My big message to the Home Secretary is do something about the Prison Service and make sure you get rid of corrupt officers.
"We don't want them in our union and we certainly don't want them serving the public in the Prison Service."
He added: "When police officers earned a good deal more than they do now, levels of corruption were less because people got paid better and also because they were interviewed appropriately, their background was checked, they were vetted more severely than potential police officers.
"That's all gone by the wayside on the altar of making economy savings on behalf of the Government."
Mr Caton said corrupt officers were "dangerous and unacceptable" and should be rooted out of the system.
If it was true that there were 1,000 or more corrupt officers, "we want rid of them, not tomorrow, not in a week's time, but now", he said.
Mr Caton said on the BBC Radio 4 Today programme: "If the Prison Service has sat on this report, or was aware in any way that there is corruption to this extent and inappropriate relationships to this extent, I find it absolutely unforgivable that they have done nothing about it and certainly haven't discussed it with us."
He added: "I joined the Prison Service in 1977. It was then a stricter vetting process, a lot stricter interview process to get into the Prison Service than the police, for obvious reasons."
Since then, vetting has becoming more lax, because management has put "a greater emphasis on reducing the amount of pay the prison officers get and their conditions of service, than tackling issues like this", he said.
He said that searching should be used in an "appropriate" way to prevent illicit items being brought into jails by visitors or staff, but said that time pressures were reducing officers' ability to do this.
"We don't want to see corrupt prison officers," said Mr Caton. "The people who corruption affects most are fellow officers.
"What we need to do is get back to a culture where prison officers feel respected for themselves, where they are respected by those who profess to run the Prison Service and where politicians recognise the very difficult and dangerous job we do and pay us appropriately and get rid of people who are corrupt or having inappropriate relationships."
Criminology professor Tim Newburn, of the London School of Economics, carried out a report on corruption for the Prison Service six years ago.
He told Today: "This isn't a small problem. This is an institutionalised, widespread set of misbehaviours - albeit by a very small minority of staff - with a significant problem for control, order, discipline and crucially for ethical conduct within the Prison Service.
"If professional standards are not being upheld, it is almost impossible to imagine that constructive work can be done in prisons."Reuse content