The prison population has fallen to its lowest level since the start of this decade after a jump in the number of offenders living in the community under an early release scheme.
Official statistics show there were 82,694 inmates in jails in England and Wales on Friday.
This is the lowest figure recorded since the weekly snapshot was first published in its current format in April 2011.
When state-run immigration removal centres are included, the last time the combined total was lower was in January 2010.
Part of the dip in the number of prisoners is due to an increase in the use of home detention curfew (HDC), under which offenders serve the remaining weeks or months of their sentence outside jail.
The latest Ministry of Justice figures show the HDC caseload currently stands at 3,304 after rising by 50% in just under six months.
In January prisons and probation services were issued with new instructions after it emerged only a small proportion of eligible prisoners were being freed under the programme.
HDC was introduced in 1999 to provide a “managed transition” from prison to community for offenders serving short custodial terms.
Prisoners jailed for at least three months and less than four years can be considered for release on HDC.
Depending on the length of the sentence, an eligible inmate can leave jail between two weeks and four-and-a-half months prior to the date at which they would otherwise have been released.
Criminals in several offence categories are either barred or “presumed unsuitable”, including sex offenders, terrorists and foreign national prisoners facing deportation.
Post-release, an individual on HDC is made to wear an electronic tag and must abide by a curfew until they have reached their automatic or conditional release date.
Early in the new year prisons and probation agencies were issued with revised guidelines on the process for considering HDC releases.
The document, circulated by HM Prison & Probation Service, said: “The reason for the change is that the previous process had become overly bureaucratic and tended to frustrate the objectives of the scheme, meaning that only a minority of eligible offenders were being released on HDC.”
Citing figures showing that only 21% of potentially eligible offenders were released under the scheme in 2016, the instruction emphasised that refusing HDC for prisoners who qualify should be the “exception”.
The HDC caseload as of Friday is 1,108 higher than the figure of 2,196 recorded on January 5, two days after the new guidance took effect.
The prison population, which almost doubled between 1993 and 2016, has come under scrutiny after violence and self-harm behind bars reached record levels.
Alex Hewson, of the Prison Reform Trust, said: “The recent reduction in the prison population is welcome, and reflects a sensible and measured streamlining of existing guidance for home detention curfew.
“Getting low risk individuals out of prison a few weeks early on a curfew gives them the opportunity to re-establish themselves in their local community, and has the additional benefit of providing some vital breathing room for a system under intense pressure.”
A Ministry of Justice spokeswoman said: “We want to see the prison population come down, but public safety is paramount and we will not set an arbitrary target to reduce it.
“No one is allowed out of prison without a thorough risk-assessment, close monitoring and strict licence conditions.
“Those who break these rules will be returned to prison and spend a lot longer behind bars.”
The ministry emphasised that it was not expanding the HDC scheme to allow the release of any prisoner who was not already eligible.