How is the Planning System working to resolve Prison Capacity?

Whilst the Sentencing Act 2026 looks to reduce prison capacity pressures, we revisit the Government’s strategy to improve supply across the prison estate.

Recent reporting on pressures across the prison estate, alongside the Government’s decision to remove most short custodial sentences, as set out in the Sentencing Act 2026 (“2026 Act”), has reinforced the message that England’s prison system is operating near the limits of capacity. The 2026 Act measures are aimed at reducing demand in the system and should be considered in the context of the parallel challenge of increasing supply. It is therefore timely to revisit the Government’s strategy for expanding prison capacity, and in particular the evolving role of the planning system in enabling delivery.

Labour’s manifesto committed to the delivery of approximately 14,000 additional prison places. That ambition is set out in more detail in the Ministry of Justice’s 10‑Year Prison Capacity Strategy dated December 2024 (the “Strategy”), which provides that additional places will be delivered through three principal routes: around 6,500 places through new prisons; approximately 6,400 places through new houseblocks within existing prisons; and a further 1,000 places through Rapid Deployment Cells. Together, these proposals represent a significant programme of new development and expansion, much of which sits directly within the planning system.

The position in relation to new prisons is comparatively settled. The Strategy indicates that these schemes are already either consented or benefit from outline planning permission. By contrast, there is considerably less clarity as to the planning status of new houseblocks within the existing estate. While it appears that a number of expansions already benefit from consent — including at HMP Standford Hill, HMP Channings Wood, HMP Highpoint and HMP Wayland, which together deliver around 1,400 places — public reporting does not clearly identify the planning position on all intended schemes.

That uncertainty is particularly acute in relation to the Government’s “Small Secure Houseblocks Programme” and “Accelerated Houseblocks Delivery Programme”, which are together expected to deliver around 3,000 additional places. It is not clear whether these programmes rely on existing permissions, permitted development rights, or future applications yet to be secured. What is clear from the Strategy, however, is that planning delay has already been identified as a material constraint on delivery.

The Strategy expressly refers to the time taken to secure planning permission for new houseblocks, including the seven‑month determination period for HMP Standford Hill. It also highlights that three new prisons were ultimately consented via planning appeals, resulting in delay and increased cost. These examples illustrate the Government’s concern that existing planning routes may not be sufficiently responsive to the urgency and scale of the prison capacity challenge. We have set out the options below.

Options for streamlining delivery

In response to these issues, successive governments have explored whether alternative consenting mechanisms might better support delivery. At one stage, there was speculation that prisons might be brought within the Nationally Significant Infrastructure Projects (“NSIP”) regime under the Planning Act 2008. While this would have offered a bespoke national consenting route, that option now appears to have been discounted. That could be due to the need for primary legislation or the availability of more flexible alternatives within the existing planning framework.

Other mechanisms have also been considered, including Special Development Orders (“SDOs”) and the use of ministerial call‑in powers. Although SDOs can grant permission for defined categories of development, they are highly visible exercises of executive power and are frequently criticised for bypassing local democratic control. Their routine use for ongoing prison expansion would therefore be politically sensitive. Similarly, while call‑in powers can be effective in individual cases, they were designed to operate on an exceptional basis and are ill‑suited as a systematic delivery tool.

Nationally Important Crown Development

Against that background, recent reforms to the Crown Development regime represent a significant recalibration of the planning system’s approach to nationally important public infrastructure. These reforms are underpinned by amendments made by the Levelling‑Up and Regeneration Act 2023 to the Town and Country Planning Act 1990, which came fully into force on 1 May 2025. Together, they establish a new consenting pathway for a new crown development regime.

Under this regime, a Crown authority (described in the legislation as the “appropriate authority”) may apply directly to the Secretary of State via the Planning Inspectorate, rather than to the local planning authority, where a proposal is considered to be of “national importance”. While distinct from the NSIP regime, the structure is reflective of the section 35 direction process under the Planning Act 2008, which allows projects to be treated as NSIPs where they are of “national significance”.

Planning Practice Guidance states that reference should be made to the February 2025 Ministerial Statement in determining what development could be “nationally important”. In summary, development may qualify where it involves national security or foreign governments; contributes to national public services or infrastructure, such as new prisons, defence or border infrastructure; supports responses to internation, national or regional civil emergencies; or would otherwise have significant economic, social, or environmental effects giving rise to strong public interest at a regional or national level.

Once an application is accepted into the regime, the Planning Inspectorate assumes responsibility for publicising the proposal, consulting statutory consultees and managing representations. Local planning authorities retain a role in the process, including through site notices and participation in hearings, but the determination of the application is removed from local development management. The default procedure is expected to be by hearing, with decisions taken in accordance with the development plan unless material considerations indicate otherwise.

Urgent Crown Development

For development that is both nationally important and required as a matter of urgency, a further route exists for “Urgent Crown Development”. In such cases, an appropriate authority may apply directly to the Secretary of State for determination. The assessment of urgency is driven by whether the development needs to be operational within a timeframe that would be unachievable through other application routes. While this mechanism offers maximum flexibility, it does not disapply environmental impact assessment requirements, and consultation remains a matter of discretion rather than elimination.

Planning policy amendments

Alongside procedural reform, the Strategy makes clear that prison development is also intended to be supported by a strengthened policy framework. The current National Planning Policy Framework (“NPPF”) already requires significant weight to be given to new, expanded or upgraded public service infrastructure.

The proposed revisions to the NPPF reaffirm this approach and embed it more explicitly within the social objective of sustainable development. In particular, the proposed NPPF emphasises the need for the planning system to support public service infrastructure that reflects current and future needs, with criminal justice infrastructure now expressly included within the definition of public service infrastructure. There is also an increasing emphasis on ensuring that local development plans address such infrastructure, reducing the risk that decisions are made in the absence of a relevant local policy framework.

Implications

Both the Written Ministerial Statement and the Strategy refer to use of the crown development route in the case of new prisons. The Strategy does not refer to a need for a new prison that has not been consented. The impact of the Sentencing Act 2026 is forecasted to result in a significant reducing in demand. Therefore, there is a question over the extent to which this Government intends to use these new strengthened provisions.

However, the implications of the new Crown Development regime extend beyond new-prisons. There appears to be no barrier to its deployment for other prison‑related development, including new houseblocks within existing establishments. More broadly, the wide definition of “national importance” means that the regime could also apply to consulates, embassies, asylum accommodation, military barracks or emergency healthcare facilities.

Viewed in that light, the recent focus on prison capacity provides a useful illustration of the wider shift underway within the planning system. Collectively, these reforms demonstrate an increasing willingness on the part of Government to recalibrate planning procedures and policy weightings to facilitate the timely delivery of nationally important development, without wholesale reform of the NSIP regime itself.

Our team has extensive experience in advising on nationally important development schemes, so please contact Gary Soloman or Douglas Haycock if you have any queries.