Ministers must build 53,000 new prison spaces to keep up with demand and ensure criminals are properly punished, according to a new report by think-tank Policy Exchange.
The study warns that more jail space is required to protect the public, with projections of almost 40,000 more spots needed.
This contrasts with Labour's long-awaited sentencing review, due to be published later this month, which is expected to recommend sending fewer criminals to jail.
The think-tank's report noted that only 46 per cent of "hyper prolific offenders" with 45 or more previous convictions who appeared in court during 2023 were sentenced to custody.
10,000 prison spots are needed to prevent overcrowding
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The report stated: "It is difficult to conceive of a statistic which more demonstrates the contempt with which the criminal justice system is treating the law-abiding majority.
"There should be capacity within the prison system for every single one of the most prolific offenders to be sentenced to a lengthy term of imprisonment to be served in full. We therefore recommend that the government increase their ambitions substantially."
Former chief inspector of prisons Peter Clarke has supported the new report, saying: "The reality is that there is no realistic alternative to increasing the capacity of our prisons.
"Not to do so would amount to an acceptance that the protection of the public is no longer the highest priority – an obviously untenable position for any government."
Clarke emphasised that more prison spaces must be made available "as a matter of urgency."
The report said the Ministry of Justice should deliver 14,600 prison places already promised, plus a further 10,900 to meet prisoner forecasts within the next five years.
Additionally, 17,500 prison places need to be created in the next ten years to "guarantee that every violent and prolific offender receives a prison sentence on conviction" and another 10,000 to avoid overcrowding.
The report expressed concern over the wide availability of the illegal drug "spice" behind bars, which is driving violence, self-harm and debts among inmates.
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One prison officer said cracking down on the illegal drug, spice, feels 'impossible'
PAThe synthetic cannabinoid is being hidden inside legally privileged papers sent into jail from outside, which cannot be scrutinised by guards without specific authorisation.
One prison officer explained to researchers that a "crackdown on spice feels impossible".
Justice Secretary Shabana Mahmood has expressed interest in a "good behaviour" scheme after visiting jails in Texas, which have been running a similar scheme for nearly two decades.
However, it remains unclear whether any version adopted by Labour would require all offenders to show good conduct for a sentence discount or offer an additional reduction.
A Ministry of Justice spokesman responded: "This Government inherited overcrowded prisons, days from collapse. We introduced emergency measures last summer but we were always clear that longer term action was required.
