Heathrow Expansion: How Affected Landowners and Businesses Can Prepare

Where the scheme stands in October 2026

The Government has chosen Heathrow's own scheme for expansion over a rival proposal: a northwest runway of up to 3,500 metres, with the M25 realigned in a tunnel beneath it, a new Terminal 5X west of Terminal 5, and upgraded roads and public transport.

In June 2026 it published the draft Heathrow Expansion National Policy Statement (HENPS), a revised version of the 2018 Airports National Policy Statement. The draft designates the scheme Critical National Growth Infrastructure. Consultation on the draft closed on 1 September 2026. The Government will consider the responses and a Parliamentary Select Committee report before deciding whether to designate an amended statement, which requires a House of Commons vote. At the time of writing it has not been designated.

Heathrow is consulting on its proposals from 27 October to 22 December 2026. The Government expects Heathrow to submit its Development Consent Order (DCO) application by the end of 2027 and anticipates a decision in the first half of 2029. Reports in September 2026 suggested that the runway itself may not open until the late 2030s.

Who is affected

The most direct effects fall on land needed for the runway, the realigned M25, the new terminal and associated roads, rivers and construction areas. Heathrow has identified a Compulsory Purchase Zone which it estimates includes more than 750 homes, mainly in Harmondsworth and Longford, together with farmland, industrial estates and other commercial premises. Communities including Sipson, Harlington, Colnbrook, Poyle, Brands Hill and Stanwell Moor are close to the works or affected by realigned roads.

The effects reach further than the boundary. Noise, construction traffic, changes to flight paths and the demand for land from displaced businesses will affect property and development prospects across Hillingdon, Hounslow, Slough, Spelthorne, Iver and the Colne Valley.

Why prepare now, whatever the timetable

A decision on the Development Consent Order is not expected until 2029, and the runway may not open until the late 2030s. That can make it tempting to wait. But the evidence that most affects an owner's position is easiest to gather now, before the scheme is fixed, before blight affects tenants and values, and before circumstances on the ground change.

Preparation is useful whatever happens to the timetable or the boundary. It means knowing exactly how the latest plans affect your land, establishing what the land could be permitted for without the scheme, recording how it is used today, and deciding who will advise you on planning, valuation and legal matters. Owners who have done this can respond quickly and consistently at every stage.

Why the 22 December consultation matters

Reforms under the Planning and Infrastructure Act 2025 removed the formal statutory pre-application consultation requirements for nationally significant infrastructure projects. Promoters are still expected to engage with those affected, but there is no guarantee of another full consultation before Heathrow applies.

That makes this consultation the main opportunity to influence the scheme while it can still change: where the red line is drawn, whether land is needed permanently or only during construction, how access to retained land and businesses is maintained, and what mitigation is offered. Points raised now also form the starting record for the examination.

What a good consultation response covers

• Your interest in the landIdentify the land, your interest in it (freehold, leasehold, tenancy or occupation) and how it is used today, with a plan.
• The specific effect on youExplain exactly which parts of the proposals affect your land or business, rather than general objections to expansion, which national policy has already settled.
• Alternatives and refinementsWhere land is not genuinely needed, or could be returned after construction, say so and suggest a practical alternative.
• Access and severanceSet out what is needed to keep retained land, homes or businesses usable during and after construction.
• Planning potentialRecord any development potential the land has, such as allocations, planning history, grey belt status or pending applications. This becomes important when compensation is assessed.
• Mitigation and property schemesComment on whether the proposed mitigation, compensation and property schemes are adequate for your circumstances.

After the consultation: the DCO examination

Once the Planning Inspectorate accepts the application, anyone can register as an Interested Party by making a relevant representation within the published period. Interested Parties can submit written evidence and take part in hearings, including compulsory acquisition hearings, during an examination that normally lasts up to six months.

Because the HENPS establishes the need for expansion, the examining authority is likely to give little weight to arguments that Heathrow should not expand. Representations about the detail, such as land take, access, design, mitigation and the justification for compulsory acquisition of particular plots, carry far more weight.

Planning evidence and compensation

Compulsory purchase compensation is assessed on the basis of the "no-scheme world": what the land would be worth if the scheme had never been proposed. For many owners, planning potential is the largest single factor in that value.

Where land is to be acquired compulsorily, the owner or the acquiring authority can apply to the local planning authority under section 17 of the Land Compensation Act 1961 for a Certificate of Appropriate Alternative Development. The certificate states what development would have been appropriate without the scheme, and compensation is then assessed on that basis. A well-prepared planning case can make a significant difference.

Valuation and legal rights are matters for an RICS surveyor and a solicitor. Heathrow has an Interim Property Hardship Scheme, and some owners may be able to serve a statutory blight notice. It has also said it intends to introduce a property bond and relocation support for residents in the Compulsory Purchase Zone. Planning consultants contribute the planning evidence on which valuations and certificates rely.

Businesses that need to relocate

Industrial and logistics land around Heathrow is already scarce, and displaced businesses will compete for the same sites. Starting early matters. Replacement premises may need planning permission for a change of use, new buildings or operational changes, sometimes in the Green Belt or Colne Valley where a careful case is required. See our commercial and industrial planning and highways advice services.

How to get prepared

• 1. Check where you standReview the latest scheme plans for your land and note the permanent land take, temporary construction land, realigned roads and timing that affect you.
• 2. Establish planning potentialFind out what your land could be permitted for without the scheme: planning history, allocations, Green Belt or grey belt status and constraints. This underpins any later compensation claim.
• 3. Record current useCollect title plans, leases, planning permissions and records of how the land and buildings are used today, including access and operational needs.
• 4. Assemble your advisersA planning consultant for the planning case, a surveyor for valuation and compensation, and a solicitor for legal rights, working from the same evidence.
• 5. Respond at each stagePut your position on record in Heathrow's consultation (27 October to 22 December 2026), then register as an Interested Party when the application is accepted.
• 6. Plan relocation earlyIf your business may need to move, start identifying replacement sites and their planning prospects now, before demand around Heathrow peaks.

Local planning advice

Hillingdon · Hounslow · Slough · Iver & Denham · Spelthorne