Many may not realise the Fukushima disaster in 2011 continues to have a major influence on development to the south of Reading. Nick Kirby (pictured left), planning director at the Thames Valley office of Lichfields, with input from senior director Dan Lampard (right), explores how planning is affected by AWE Burghfield’s Detailed Emergency Planning Zone (DEPZ), which was extended as a result of the tragedy. 

Whilst Fukushima in Japan is 6,000 miles from the Thames Valley, the meltdown of three reactors at the Daiichi nuclear plant there, following the 2011 earthquake, continues to impact on the delivery of development within parts of West Berkshire, Wokingham and Reading. 

Recent decisions by both a planning inspector and Reading Borough Council however suggest that the impacts of the constraints imposed in Spring 2020 may be being reduced – particularly for smaller residential schemes.


The Atomic Weapons Establishment (AWE) facilities at Burghfield and Aldermaston are nuclear licensed sites with the role of manufacturing, maintaining and developing nuclear weapons for the Ministry of Defence.  Both locations have, for many years, formed an important consideration in planning for new development in the region particularly in West Berkshire, Wokingham and Reading.

In particular the Detailed Emergency Planning Zone (DEPZ) that surrounds both locations has constrained new residential development in certain locations where it could increase human risk in the event of an accident occurring at this nuclear site.  The DEPZs reflect the risks from events regarded as having a low likelihood of occurrence but a high impact if they do occur.

Whilst the DEPZ does not constitute a legal ‘exclusion zone’ around the AWE facilities, they do form a material consideration in the determination of planning applications.  Similar provisions apply across all three local authorities – for example planning policy relating to schemes within the DEPZ  in Wokingham are required to demonstrate that the increase in the number of people can be safely accommodated having regard to the needs of ‘blue light’ services and the emergency AWE off site plan.

Changes to the extent of the DEPZ

Spring 2020 saw a notable change in the approach to planning in proximity of AWE resulting from a reassessment in the extent of the DEPZ leading to a significant widening in the zone of protection. The changes responded to the Radiation (Emergency Preparedness and Public Information) Regulations (REPPIR) which were updated in 2019 (in response to events in Fukushima) and key amendments include:

  • They gave responsibility for defining the DEPZ to the lead local authority, which for AWE Burghfield is West Berkshire District Council, whereas previously this had been the responsibility of the Office for Nuclear Regulation;
  • They amended the way in which the geographical extent of the DEPZ was determined to include greater consideration of factors such as weather conditions, causing the size of the DEPZ to significantly increase; and
  • The DEPZ was also no longer defined as a circle, instead it reflected a larger and irregularly shaped area that takes account of the settlement pattern and the roads connecting them

The impact of the amended DEPZ was that development land previously considered potentially suitable for development, became subject to a significant constraint. Notably the widened DEPZ included Grazeley Garden Town which was being proposed to provide up to 15,000 homes and was generally supported by Wokingham, Reading and West Berkshire Council.

The promoters of Grazeley (Hallam Land, Crest Nicholson Operations and Wilson Enterprises) pursued an unsuccessful High Court challenge against the process leading to the extended DEPZ.  Subsequently, in November 2021 Wokingham borough council confirmed with their Local Plan Update : Revised Growth Strategy that “in light of the changed circumstances, the Grazeley Garden Town proposal, and therefore the strategy proposed by the Draft Local Plan (February 2020), is no longer achievable”.

Initial planning decisions

Subsequently other developers (in some instances during the determination of planning applications appeals) found their sites suddenly falling within the extended DEPZ and their proposed developments subject to a constraint not envisaged at the time the planning application or appeal was submitted.

Bewley Homes submitted a Written Representations appeal against Wokingham Borough Council’s refusal of planning permission for the erection of 24 new homes at land to rear of Diana Close, Spencers Wood[1] in February 2021. The DEPZ had been extended after the refusal of the planning application and therefore the suitability of the site having regard to the DEPZ became one of the main issues considered by the Inspector during the appeal, despite it not being so during the planning application stage.

The inspector dismissed the appeal noting they considered it “necessary to adopt a precautionary approach”.

Similar decisions followed.  In dismissing an appeal for three dwellings at Grazeley Road, Three Mile Cross[2] in August 2021 the inspector considered “the proposal has the potential to have a harmful effect on the blue light services, as well as the off site plan for the AWE”.

In September 2021 in dismissing an appeal for four dwellings at the Hearn and Bailey Garage[3], Three Mile Cross the inspector concluded that “while the risk is very small and the size of the development modest it would have an adverse effect on public safety with regard to off-site nuclear planning arrangements for the AWE”.  

But subsequently…

An appeal decision was issued in January 2023 permitting JPP Lands’ proposals for the erection of 49 dwellings at Kingfisher Grove[4] following the failure of WBC to determine the application. One of the main issues the inspector assessed was whether the proposed development could be safely accommodated given the site’s proximity to AWE Burghfield, with the associated risks of an incident releasing radioactive material into the atmosphere.

Unlike the earlier appeals this decision followed a public inquiry where evidence put forward by both the appellants and WBC was tested. The inspector drew the following conclusions (in respect of that site) which led to the appeal succeeding:

    • The risk of an incident occurring would be very small – the appellants modelling suggested an event could occur on a one in 10,000 year basis
    • Considering the risk to the appeal site specifically taking into account factors such as wind conditions and adherence to the REPPIR emergency plan further reduces the risk of a person on the appeal site being harmed by such an incident to a single event in many more thousands or millions of years
    • Sheltering during an incident would be the primary method of protection to human health and this would be expected to be over a short period of less than two days
    • Despite blue light services expected to be working at capacity during an incident, these resources would be primarily focused on a localised area of the DEPZ over which the dispersed plume would pass, which would not compromise the delivery of emergency plan
    • In terms of the risks for a person at the appeal site in the event of exposure to radiation, this was expected to be low at 1.5 millisieverts (a measure of radiation) – this was considered “minor” when 20 millisieverts is the annual legal worker dose

Interestingly, Reading Borough Council (RBC) also recently granted planning permission (issued on March 10, 2023) for a Gypsy and Traveller transit site at Island Road in Reading. The site falls within the DEPZ for AWE Burghfield and RBC faced objections from the AWE Offsite Planning Group, RBC’s emergency planning officer and the Joint Emergency Planning Unit (covering Bracknell Forest, Windsor and Maidenhead and West Berkshire) as well as the Office for Nuclear Regulation (ONR) who all contended that the proposals conflicted with the requirements of the DEPZ.

RBC Officers, whilst accepting that “a family stuck for 48 hours in a [2.4 sq m] sanitary block is not going to be a pleasant experience” went on to conclude that the “relevant emergency planning specialists are not advising that they would be unsafe in doing so, if they heed the instructions”,   RBC officers therefore recommended granting the planning permission, with a planning condition attached requiring that a detailed site specific emergency plan be submitted before development commenced and Members concurred with this decision.


Overall, the changes arising from the enlarged DEPZs clearly imposed restrictions on planning for new development in certain locations not previously within it. Importantly however these restrictions are in the form of a planning “material consideration” rather than an “embargo”.

Planning inspectors initially trod cautiously in considering this matter, with the Diana Close inspector acknowledging she was adopting a “precautionary approach”.

In a context where planning applications are considered on their merits, and the recent decisions by both RBC and the Kingsgrove Grove are rooted in the specific circumstances of these cases, it is generally inappropriate to draw sweeping conclusions – but here are three thoughts from us :

  • Testing the scientific basis of potential risks through a cross examination process during the Kingfisher Grove appeal led the inspector to conclude that a modest level of residential development at the appeal site could proceed without an unacceptable level of risk;
  • RBC Officer and members have been prepared to challenge, and ultimately defy, the combined forces of the ONR, the AWE Offsite Planning Group, the Joint Emergency Planning Unit and their own emergency planning officer concluding that their concerns were appropriately assuaged by a planning condition; and
  • Whilst these two specific decisions do not equate with a dam bursting we expect detailed assessment of the risk of developing sites in affected areas will continue to be an important consideration for planning applications and appeals. At this stage the two permitted schemes equate to just 56 dwellings / pitches which indicate that it may continue to be harder for larger schemes to demonstrate compliance with the AWE Emergency Plan.

[1] PINS ref. APP/X0360/W/19/3240232

[2] PINS ref APP/X0360/W/19/3240232

[3] PINS ref APP/X0360/W/21/3271017

[4] PINS ref. no. APP/X0360/W/22/3304042

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