Lancashire has one of the highest sex offender populations in England and Wales.
Police forces, probation services and other government agencies keep tabs on dangerous criminals living in communities in England and Wales using special management plans known as Multi-Agency Protection Arrangements.
New Ministry of Justice figures reveal that 2,101 registered sex offenders were being managed under MAPPA in the Lancashire Constabulary area as of March this year.
At a rate of 159 in every 100,000 people, that means Lancashire has one of the highest concentrations of sex offenders out of prison in England and Wales.
More than 60,000 sex offenders are registered with police forces across the two countries.
Children’s charity the NSPCC said while the figures were concerning, they were only “the tip of the iceberg”.
A spokeswoman said: “The scale of the problem is deeply concerning, but it is encouraging to see that more offenders are coming to light and being put on the list of registered sex offenders, particularly as many of these could have committed the most serious sexual offences against children.
“We know from our own research that recorded child sexual offences are at an all-time high and it’s crucial that the system is able to cope to ensure offenders are being properly monitored in the community.
“But these figures are the tip of the iceberg so it is vital to report signs of sexual abuse where they occur.”
Sex offenders who are sentenced to at least 30 months in prison remain on the register indefinitely – although some can apply to be removed after 15 years following a change to the law in 2012.
Lancashire Constabulary removed four people from the register following an application last year.
Over the last five years, the sex offender population in Lancashire has increased by 521, or 33 per cent.
That is in line with the pace of growth across England and Wales as a whole, where the pool of offenders needing MAPPA management increased by 31 per cent.
Registered sex offenders are split into three categories, depending on how serious a risk they pose to the public, and what degree of management they need.
The vast majority are level one offenders, which means police and other agencies share information about them, but no special measures are required.
But offenders in Lancashire were placed in the level two category 19 times during 2018-19, meaning agencies have to hold regular meetings to discuss them, while three were deemed to be level three, the most serious kind.
These offenders pose such a big risk that additional resources such as specialised accommodation may be needed to manage them.
Registered sex offenders have to tell police of any changes to their circumstances, such as their address, foreign travel plans, and potential contact with children.
In Lancashire, 66 offenders were cautioned or convicted for failing to do so last year.
The figures also show that 831 violent offenders were living in Lancashire in March.
This could include other sexual offenders not on the register, as well as those who have committed crimes such as murder, kidnapping and grievous bodily harm.
A Ministry of Justice spokeswoman said: “Since 2010, more perpetrators of sex offences are being convicted, sentenced and imprisoned.
“This Government is overhauling the criminal justice system - investing £2.75bn in prisons, recruiting 20,000 new police officers and changing sentences to protect the public from the most violent and sexual offenders.”