Government guidance requires the policies in local plans be based upon sound evidence. Here you can find out about the studies we have undertaken to meet this requirement.

Evidence Base for the New Local Plan

We are currently working on a new Local Plan for the borough, which includes gathering a substantial amount of new and updated evidence. New documents will be added to this section as they become available.

Local Plan Interim Sustainability Appraisal 2024

Local Plan Interim Sustainability Appraisal 2024 (Draft)

This Interim Sustainability Appraisal has been prepared by LUC on behalf of Hertsmere Borough Council as part of the integrated Sustainability Appraisal (SA) and Strategic Environmental Assessment (SEA) of the Hertsmere Local Plan.

The Interim SA provides an appraisal of a newly identified development approach and a number of new and amended site options that have been identified since the last iteration of the SA. A full updated SA report, incorporating the work included in this Interim SA, will be prepared at the next stage of plan-making.

Assessment and comparison of Green Belt housing and employment sites, March 2024

The assessment and comparison of sites is the first stage in the updated site selection process for the revised Local Plan. The output from this process is a site comparison matrix for housing and employment sites. Each site is given a matrix score according to how well it performs in relation to Green Belt and other environmental factors. The relative scores achieved by each site have informed the process of making final site selections for the Regulation 18 consultation being undertaken in 2024.

Assessment and comparison of Green Belt housing and employment sites, March 2024

South West Hertfordshire Local Housing Needs Assessment 2020

Following the introduction of the Government’s standard methodology for assessing local housing need, a Local Housing Needs Assessment has been commissioned jointly with Dacorum, St Albans, Three Rivers and Watford councils. The report is available below.

South West Hertfordshire LHNA 2020 (8.52mb)

Draft Housing and Economic Land Availability Assessment (HELAA) 2024 

The Housing and Economic Land Availability Assessment (HELAA) is a technical study prepared to inform the Council’s new Local Plan. The assessment and identification of sites has no status in formally allocating land for future development and will not be treated as a material consideration in any future decision that the Council makes on individual planning applications. The Draft HELAA report is provided giving the opportunity for comment prior to finalising the study. Should you wish to comment on the HELAA please email:

Previous versions of the HELAA.

This version of the HELAA has been broken down by settlement for ease of viewing.

Please note the site maps will be updated in due course for greater clarity.

Draft HELAA Report 2024 (PDF 2.13MB)

HELAA Index (PDF 537Kb)

Borehamwood and Elstree

Pro-formas (PDF 2.94MB)

Maps (PDF 19.33MB)

Elstree Village

Pro-formas (PDF 967Kb)

Maps (PDF 3.67MB)


Pro-formas (PDF 2.27MB)

Maps (PDF 16.06MB)

Potters Bar

Pro-formas (PDF 2.12MB)

Maps (PDF 18.12MB)


Pro-formas (PDF 1.89MB)

Maps (PDF 11.17MB)


Pro-formas (PDF 1.37MB)

Maps (PDF 8.37MB)

South Mimms

Pro-formas (PDF 1.59MB)

Maps (PDF 6.33MB)

Other Sites

Pro-formas (PDF 1.64MB)

Maps (PDF 10.45MB)

Employment Sites

Pro-formas (PDF 2.94MB)

Maps (PDF 19.88MB)


South West Hertfordshire Strategic Housing Market Assessment (SHMA)

When the Core Strategy was adopted in 2013 we undertook to review housing and employment development needs within three years to help inform future plan-making. The council jointly with Dacorum, Three Rivers and Watford Council's commissioned consultants in 2015 to prepare two interlinked studies, the SHMA (produced by GL Hearn) and the Economic Study (Regeneris, assisted by GL Hearn).

The purpose of the SHMA is to assess future development needs for housing (both market and affordable) across the relevant housing market area (HMA). Based on the evidence, the South West Hertfordshire HMA is defined as covering the four commissioning authorities, plus St Albans District.

The SHMA considers housing need arising over the 2013 to 2036 period, to inform local plans. It considers the need for different types of housing and the housing needs of different groups within local communities.

SHMA documents

South West Herts SHMA Main Report (PDF 2.87mb)

South West Herts SHMA Executive Summary (PDF 958kb)

South West Herts SHMA Appendices (PDF 3.92mb)

Workshop Report (PDF 1.63mb) (relates to both the SHMA and Economic Study)

South West Hertfordshire Retail and Leisure Study (2018)

South West Herts Economic Study 2019 and 2016

The Economic Study provides comprehensive economic baseline and growth scenarios for South West Hertfordshire. An update to the 2016 study has recently been completed in September 2019. 

This updated 2019 study reviews the conclusions and recommendations of the previous 2016 study, and provides an objective assessment of the long term employment land and premises needs over the period 2018 to 2036, including an evaluation of the current and future supply. Furthermore, the 2019 study looks at possible local authority planning and strategic responses.

The 2016 study identified the scale and characteristics of employment growth that the functional economic market area (FEMA) might plan for over the 2013-2036 period, and the requirements for employment land and floorspace that this entails. In light of the evidence, the SW Hertfordshire FEMA covers the same area as the HMA defined in the SHMA i.e. the commissioning authorities and St Albans. This is still considered the case.

The economic studies provide a high level review of some existing employment areas and potential future sites. They also consider whether there is likely to be sufficient land supply to meet the needs of the South West Hertfordshire economy.

Because it is so important to understand the future need for homes and jobs, the studies have been subject to extensive consultation with technical stakeholders. This has included a workshop, for which a separate report has been published.

The SHMA does not set housing targets, nor does the Economic Study set targets for job growth or floorspace increase. Both studies provide important inputs into the setting of these targets.  However, the actual targets will be set by each local authority in future local plans. When setting these targets, the authorities will take account of the SHMA and Economic Study and a range of other factors.  These factors will include the supply of land for new development, the Green Belt, local infrastructure capacity and environmental constraints. These factors may limit the amount of development which can be accommodated sustainably.

The targets included in local plans may also be affected by the outcome of discussions under the Duty to Co-operate between the commissioning authorities and neighbouring and nearby authorities.

Economic Study documents

South West Herts Economic Study 2019 (PDF 5.93mb)

South West Herts Economic Study 2016 (PDF 12.94mb)

Workshop Report (PDF 1.63mb) (relates to both the SHMA and Economic Study)

Sustainability Appraisal (SA) and Habitats Regulation Assessment (HRA)

The Sustainability Appraisal Report and Habitats Regulation Assessment have been prepared by LUC as part of the integrated Sustainability Appraisal (SA) and Strategic Environmental Assessment (SEA) of the Hertsmere Local Plan. These reports presents an assessment of the Draft Local Plan (September 2021) for Hertsmere.

These reports serve as live documents and will continue to be updated to accurately reflect Hertsmere's Local Plan. An initial draft version of both documents has been published to correspond with the Regulation 18 public engagement. However, an updated version of both these documents will be made available shortly.

The SA process involves appraising the likely social, environmental and economic effects of the policies and proposals within a plan from the outset of its development.

Draft Local Plan Sustainability Appraisal Report (Oct 2021) (4.22mb)

Draft Local Plan Sustainability Appraisal Report Appendices (Oct 2021) (6.38mb)

HRA refers to the assessment of the potential effects of a development plan on SPAs and SACs.

Draft Local Plan Habitats Regulation Assessment (Oct 2021) (PDF 3.61mb)

Previous versions of these reports are available below:

Draft Local Plan Sustainability Appraisal Report (Oct 21 superseded)  (PDF 4.78mb)

Draft Local Plan Sustainability Appraisal Report - Appendices (Oct 21 superseded)  (PDF 4.67mb)

Draft Local Plan Habitats Regulation Assessment (Oct 21 superseded) (PDF 3.61mb)

SA Issues and Options Report (2018) (PDF 1.2kb)

SA Scoping Report Sept (2017) (PDF 718kb)

HRA Scoping Report (Sept 2017) (PDF 551kb)

SA Sites Report DRAFT (Oct 2018) (PDF 2.56mb)

Green Belt Assessment - Stage 1, 2, 3 and 4

The Stage 1 and Stage 2 Green Belt reports have been produced by Arup, consultants who were commissioned to produce an independent assessment of all Green Belt land across Hertsmere to identify how it meets national Green Belt purposes. These Green Belt purposes are set out by national Government in the National Planning Policy Framework (NPPF) and are as follows:

  • to check the unrestricted sprawl of large built up areas;
  • to prevent neighbouring towns merging into one another;
  • to assist in safeguarding the countryside from encroachment;
  • to preserve the setting and special character of historic towns; and
  • to assist in urban regeneration, by encouraging the recycling of derelict and other urban land


Arup's report does not make any recommendation for further building in Hertsmere, above what is already planned in the Council's existing Core Strategy adopted in 2013.

Green Belt Assessment Stage 1 (2016)

Hertsmere Green Belt Assessment Report (PDF 5.34mb)

Hertsmere Green Belt Assessment Annex Report (PDF 12.15mb)

Green Belt Assessment Stage 2 (2019)

Hertsmere Green Belt Assessment stage 2 Report (PDF 38.56mb)

Hertsmere Green Belt Assessment stage 2 Annex Report (PDF 146.30mb)

Hertsmere Green Belt Assessment stage 2 Appendix B Maps - HELAA, Garden Village and Further Sites considered (PDF 13.26mb)

Hertsmere Green Belt Assessment stage 2 Appendix C Maps - Sub-areas and Garden Village site (PDF 8.66mb)

Hertsmere Green Belt Assessment stage 2 Appendix D Maps - Settlement level Purpose 1 Score maps (PDF 17.04mb)

Hertsmere Green Belt Assessment stage 2 Appendix E Maps - Settlement level Purpose 2 Score maps (PDF 18.95mb)

Hertsmere Green Belt Assessment stage 2 Appendix F Maps - Settlement level Purpose 3 Score map (PDF 18.46mb)

Hertsmere Green Belt Assessment stage 2 Appendix G Maps - Settlement level Purpose 4 Score maps (PDF 18.40mb)

Hertsmere Green Belt Assessment stage 2 Appendix H Maps - Recommendation maps (PDF 18.56mb)

Green Belt Assessment Stage 2 - Additional Sites (2020)

Hertsmere Green Belt stage 2 additional sites report (PDF 39.2mb)

Green Belt Assessment Stage 2 - Additional Sub-Area Assessed (2024) - DRAFT REPORT  

Draft Additional Sites Assessment 2024 Issue 270324 (low res) (PDF 9.5mb)


Green Belt Assessment Stage 3 - Washed Over Villages (2020)

The stage 3 Green Belt report takes a closer look at the smaller settlements within the Borough. The report analyses whether it is necessary to restrict development in a washed over village/hamlet because of its contribution to openness of the Green Belt, or conversely whether the settlements inclusion in the Green Belt should be reconsidered due to the limited contribution which the open character of the village makes.

Hertsmere Green Belt stage 3 - washed over villages (PDF 21.42mb)

Green Belt Assessment Stage 4 - Inset Village Boundary Assessment (2021)

The stage 4 Green Belt  report  looks specifically at the current washed over villages of Shenley, South Mimms and Elstree Village. The report considers the potential future Green Belt inset boundaries of these three settlements.

Hertsmere Green Belt stage 4 - Inset Village Boundary Assessment (PDF 8.43mb)

Housing and Economic Land Availability Assessment (HELAA) DRAFT 2018 Maps

Gypsy and Traveller Accommodation Needs Study (2017)

Infrastructure Delivery Plan

COMET transport model

Updated and maintained by Hertfordshire County Council. The COMET model is a multi-modal transport model, developed using Department for Transport WebTAG guidance. It is able to predict changes in travel demand for vehicles, buses and rail. Further information on transport modelling within Hertfordshire can be found here.

Hertfordshire County Council (HCC) commissioned AECOM to produce a 2036 forecast using the COMET multi-modal transport model. The forecast scenario includes the Local Plan aspirations (all employment and dwelling growth, regardless of certainty) of the 10 Hertfordshire districts, as well as the growth aspirations in neighbouring areas.

Hertfordshire COMET: Local Plan Forecasting Report - LP5 2020 (PDF13.9mb)

Hertfordshire COMET: Local Plan Run 5 Forecast results - LP5 2020 (PDF 9.33mb)

The COMET model for Hertsmere (2018) has been produced by AECOM,consultants who where commissioned to produce an independent assessment by Hertfordshire County Council (HCC), of the impact on transport routes and services from a range of Local Plan allocation scenarios within Hertsmere up to 2036.

COMET transport model Hertsmere Local Plan ,2018 (PDF 11.77mb)

An additional, independent analysis of projected vehicular traffic movements has been undertaken using the COMET model as its baseline. COMET is a strategic model covering all of Hertfordshire and as such, the journey time results should only be treated as indicative and highlight areas where changes are expected.

COMET transport model - Hertsmere Local Plan Analysis, 2021 ( PDF 21.3 Mb)

COMET transport model - Hertsmere Journey Time Analysis, 2020 (PDF 4.44Mb)

Settlement Hierarchy and Accessibility Mapping

High Level Transport Assessment (2018)

Strategic Flood Risk Assessment (2018)

Open Space, Sport and Recreation Study (2019)

The Open Space, Sport and Recreation Study 2019 comprises of three separate sections. These are: The Playing pitch strategy, Indoor needs assessment and Open Space study.

Landscape and Visual Sensitivity Assessment (2020)

This study comprises two sections; a Landscape Sensitivity Assessment (LSA) and an Outline Landscape Appraisals (OLA) Report.

Secondary school site search reports

Vincent and Gorbing were commissioned by Hertfordshire County Council to undertake a search for potential secondary school sites in south-west Hertfordshire in response to secondary education need arising from potential housing and demographic growth identified during the current preparation of new local plans in the area.

Secondary School Site Search Report: Borehamwood (2021) (32.2mb)

Secondary School Site Search Report: South-East Watford and Bushey (2021) (59.3mb)

Hertfordshire Water Study (2017)

A study on water infrastructure and resources in Hertfordshire.

Sustainable Transport Appraisal 

The Hertsmere Sustainable Transport Appraisal and Outline Settlement Transport Studies were commissioned in 2021 and followed the initial High Level Transport Assessment carried out in 2018. 

It should be noted that since work on the Transport Appraisal and Settlement Studies commenced, the Local Plan context has changed.  This follows the decision of the Council in 2022 to formally set aside the Regulation 18 draft Local Plan to enable additional technical work to be carried out whilst awaiting clarity from the Government on planning reforms.  It was agreed with the consultants that the Transport Appraisal and Settlement Studies should be completed, as part of this technical work.

 Sustainable Transport Appraisal (2023) (PDF 11.86mb)

Implications of 2021 Census report (draft) (2023)

This report was commissioned to review any implications for Hertsmere's housing need from the release of 2021 Census data and up-to-date evidence on population and demographic trends.     

Implications of 2021 Census on Hertsmere’s Housing Need (Draft, 2023) (PDF 763kb)

Hertsmere Film and Television Study 2024

This study assesses the film and television production environment in the borough of Hertsmere and situates it within the regional, national, and global industry contexts.

Hertsmere Film and Television Study 2024 (PDF 2,126kb)