Where the plan is likely wrong, or needs more evidence
Each point below names the soundness test it engages and a change an Inspector could make. These are the points most likely to matter at examination.
1. The traffic impact of the Radlett sites together has not been tested
The Council's own infrastructure plan records “severe congestion on Watling Street A5183 southbound north of Radlett – stretching as far back as Colney Street”, affecting Harper Lane, plus congestion on Park Road, Theobald Street and Hartspring Lane. It calls Radlett “the only major settlement with no direct strategic road link”. (IDP, Reg 19, Highways.)
The transport study was based on the March 2026 site list, which “has now been superseded”. It says “transport mitigation requirements for sites have not been considered at this stage”, and leaves the combined modelling until “prior to the submission”. (Transport and Movement Assessment, paras 1.2.5, 5.1.11, 6.1.1.) So the 1,573-home north-west site, and the two new sites, have not been assessed at all.
For the old SA3 alone (972 homes), the study expected about 530 vehicle trips in the morning peak hour. It found “strong relative connectivity by driving and poor relative connectivity by walking”. Using the study's own rate (0.545 trips per home), the 1,573-home site would generate about 860 vehicle trips in the morning peak hour, from this one site. (TMA proforma, Land on Watford Road (north).)
The site policies leave developers to “gain an understanding of the cumulative traffic impacts” at the masterplanning stage, after the land is allocated. (Reg 19 paras 17.78, 17.95.)
- Tests
- Justified and effective (NPPF 36(b), (c)); consistent with NPPF 109, 115(d), 116 and 148.
- Change to ask for
- Publish the modelling for the actual Regulation 19 sites and consult on it before submission. Make later phases of HRA5 and HRA6 depend on named road and junction improvements being delivered first. Treat the Radlett capacities as maximums.
2. The plan's strategy for Radlett contradicts its own allocations
The plan says Radlett will take “more modest and incremental growth than the Borough's larger settlements”, “primarily through the sensitive redevelopment of previously developed land, infill development, small-site opportunities”. It aims for “careful evolution rather than major transformation”. (Reg 19 paras 17.9–17.10, p. 572; Key Spatial Objectives 1–2, p. 576.)
In practice about 91% of Radlett's 2,907 homes are on five urban extensions onto farmland. Both town-centre brownfield sites from the spring draft have gone. The Council's own engagement for Radlett found that “growth should be incremental and controlled”. (IDP Table 3-1; Radlett Key Themes and Priorities Report, October 2026.)
Radlett, with about 8,300 residents, is given 2,635 allocated homes; Bushey, with about 27,500, is given 2,793. The 2021 Census counted 3,189 households in Radlett, so 2,907 new homes is growth of about 90%. Aldenham Parish Council told the Council the same: “over 90%”. (TMA paras 3.3.14, 3.3.28; IDP Table 3-1; ONS Census 2021 TS041, area E02004900; Consultation Statement para 6.7.2.)
- Tests
- Justified (NPPF 36(b)) — the strategy and the allocations do not match. Policy HBF1(c) itself asks for an “appropriate and proportionate scale” in Radlett.
- Change to ask for
- Reduce HRA6 so that Radlett's growth matches the plan's own description of it, and name where the difference goes (see the box below).
3. The north-west site grew by 411 homes with no published reason
The spring Sustainability Appraisal said: “If Site 4 were to be removed then there would also be a case for removing the western part of Site 3”, because it “would not relate well to the settlement edge”. (Reg 18 SA para 5.4.62.) Site 4 has now been removed. The western part of Site 3 has not. Instead SA7 rose from 190 to 350 homes and two new parcels were added.
The HRA6 policy even describes the site as “located to the south of Radlett”, a sentence copied from the Home Farm policy. (Reg 19 para 17.87, p. 601.)
The plan says a Sustainability Appraisal has been published for this stage. On 8 October 2026 the appraisal on the Council's evidence page was the same file as the spring version. (Reg 19 para 1.18; evidence page.)
- Tests
- Justified (NPPF 36(b)) — reasonable alternatives, including the smaller 2021 footprint, are not shown to have been tested. Legal compliance — plans must be informed by a sustainability appraisal (NPPF 33).
- Change to ask for
- Remove the western (Cemex) part of the old SA3 and the two new parcels, or publish an appraisal that justifies them against the alternatives.
4. Schools and GP capacity are identified but not secured
The infrastructure plan says Radlett's growth needs 4 forms of entry of primary places and 3 of secondary. The County Council has identified a new 2-form-entry primary school at the north-west site, a 2–3 form-entry primary school at Home Farm, and a new 6–8 form-entry secondary school “to be located in Radlett/Bushey/Rural West”. (IDP, Reg 19, Education.)
Radlett and Shenley GP practices already lack capacity for around 6,770 patients. The local NHS integrated care board says the Red House Surgery's position “will become unsustainable without significant investment and expansion”, and wants an option for an on-site health facility at both large sites. (IDP, Reg 19, Primary healthcare.)
Yet the Home Farm and north-west policies reserve no land for schools or health. They say only that developers “will work collaboratively with the education authority … to determine the requirements”. No secondary school site is identified anywhere. (Reg 19 paras 17.79, 17.97.)
For balance: the forecast spare primary capacity in Radlett has improved since the spring, to 1.3 forms of entry by 2030-31. That is still well short of what the plan's own figures say the new homes need.
- Tests
- Effective (NPPF 36(c)); NPPF 20(c) and 35 require plans to make provision for education and health.
- Change to ask for
- Allocate land for the named primary schools and a health facility within HRA5 and HRA6. Identify and safeguard a secondary school site before confirming Radlett's allocations. Tie occupation of later phases to delivery.
5. Key evidence is cited but not published
On 8 October 2026 the Council's evidence page did not include:
- a Regulation 19 Sustainability Appraisal (the link opens the spring version);
- the Water Cycle Study (September 2026), which the Council said “will be published with the Regulation 19 draft Local Plan” (Consultation Statement, Appendix D, p. 210);
- the Level 2 Strategic Flood Risk Assessment (June 2026), described in the plan as “prepared and published” (Reg 19 para 11.54);
- any combined traffic modelling.
At the spring stage Natural England urged the Council to gather outstanding evidence and update its appraisals, warning that failure to do so “may risk the Plan being found unsound at examination”. (Consultation Statement para 6.10.1.)
- Tests
- Legal compliance; justified (NPPF 32, 33, 36(b)).
- Change to ask for
- Publish the documents now. If they appear part-way through the six weeks, extend the period so residents can comment on them.
6. Water supply is already stretched
According to the Council's Habitats Regulations Assessment, the Water Cycle Study finds Hertsmere is “within an area of serious water stress”. It finds the plan's growth exceeds the water company's planning assumptions by “approximately 11,000 dwellings”. Affinity Water says it has measures to cope. (Reg 19 HRA paras 5.5.7, 6.1.2.) Sewer capacity is left to planning applications. The plan accepts it is “not possible to identify all the infrastructure required over the Plan period”. (Reg 19 para 11.59.)
- Tests
- Effective (NPPF 36(c)).
- Change to ask for
- Publish the Water Cycle Study. Phase HRA5 and HRA6 to confirmed water and wastewater capacity.
7. Heritage at the north-west site is not named
The Council's Green Belt study places the old SA3 within the setting of five grade II listed buildings. It says this “potentially provides a strong reason for refusing or restricting development”, though mitigation may be possible. The HRA6 policy names none of them. The Home Farm and Watling Street policies do name their heritage assets. (Green Belt Assessment Stage 2, October 2026; Reg 19 paras 17.48, 17.77, 17.90.)
- Tests
- Consistent with national policy (NPPF 203, 208, 212–213).
- Change to ask for
- Name the listed buildings in HRA6 and set specific requirements for their settings.
8. The numbers and the monitoring do not line up
- The plan's total is 16,575 in Policy H1, 16,893 in Table 13.1, 16,892 in Appendix 5, and “at least 17,460” in monitoring indicator LPI 28, which leaves the Radlett figure blank. (pp. 92, 336, 669, 631.)
- The indicator for strategic transport schemes points to “Table 11.1”, which is a table of carbon offset payments, and to an “Appendix X” of the infrastructure plan. (LPI 25, p. 631; p. 271.)
- HRA5 and HRA6 are called “strategic urban extensions” but are labelled non-strategic policies. Non-strategic policies are tested “in a proportionate way”. (Reg 19 pp. 595, 600, Appendix 3; NPPF 37.)
- Tests
- Effective (NPPF 36(c)).
- Change to ask for
- Correct the figures. Add a Radlett indicator that tracks homes delivered against roads, schools and GP capacity delivered.
Two points that cut both ways
There is little spare supply. Any homes taken out of Radlett have to be found elsewhere. The plan itself names two large brownfield sites it has not counted: the Tesco store in Borehamwood and Sainsbury's in Potters Bar, which “remain as opportunities that could come forward”. Bowmans Cross has capacity for 5,000 homes, with 2,500 counted in the plan period. (Reg 19 para 3.10, p. 29; Appendix 5.)
The first five years are already short. The plan's own trajectory shows 4,524 homes in years 1–5 against a requirement of 5,850. That is a genuine weakness, but arguing it could push an Inspector towards more early sites, not fewer. Radlett has 441 homes in years 1–5 (HRA2, HRA4 and the first phase of HRA6). (Reg 19 Appendix 5, p. 669; NPPF 72, 78.)