Annexe and granny-flat drawings for Hanslope homes — designed to stay ancillary to the main house rather than become a separate dwelling, drawn to Milton Keynes City Council's policies, delivered in days and revised free until your decision.
Milton Keynes City Council granted 87% of the householder planning decisions it made in its latest published year — level with the 87% England-wide householder average. The northern parishes lie in open countryside well outside the New Town grid, so extensions and new builds are judged against rural and open-countryside policy in Plan:MK, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) and interwar (1918–1939) housing stock sets the design brief on most streets.
Before permission is required, Class B allows 40m³ of added loft volume on a terrace and 50m³ on a semi or detached house, and Class A allows a 3m single-storey rear extension on a terrace or 4m on a detached house. In conservation areas such as Hanslope, Castlethorpe and Ravenstone those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Hanslope is determined against an 8-week statutory target.
Hanslope (a stone-built village and conservation area with the county's tallest church spire), Castlethorpe (a historic village and conservation area beside the West Coast Main Line), Ravenstone (a small limestone village and conservation area to the north), Stoke Goldington (a linear stone village and conservation area on the Northampton road), Gayhurst (a historic estate hamlet with a listed hall near Newport Pagnell) and Haversham (a village on the Ouse floodplain north of Wolverton) — these are the Hanslope pockets our drawings cover most. Heritage designations here include Hanslope, Castlethorpe, Ravenstone and Stoke Goldington. Milton Keynes City Council weighs each proposal against Plan:MK (the Milton Keynes Local Plan 2019), where the historic stone village cores carry conservation-area controls on materials, boundary walls and the setting of listed buildings. On roofs the borough is pitched stone-slate, thatch and clay-tile roofs on the village cores and gabled roofs on the estate infill, over limestone and brick village cottages and farmhouses, Victorian and interwar village housing and small late-20th-century estate infill within the villages.
Councils do not decide annexes on square metres. They decide whether, once built, the accommodation forms part of one planning unit with the main house or a second one beside it. Milton Keynes City Council looks at whether the garden is shared or divided, whether the annexe has its own street access and address, whether the occupier could live there entirely independently, and whether the two households would function as one. That is the whole case, and it is made or lost on the layout.
Hanslope is largely limestone and brick village cottages and farmhouses, Victorian and interwar village housing and small late-20th-century estate infill within the villages, which shapes the realistic options: converting part of the existing house, extending it, or building a detached unit in the garden. A detached annexe can sometimes sit under Class E as an outbuilding incidental to the enjoyment of the dwellinghouse — but sleeping accommodation is generally not "incidental", so a garden annexe with a bedroom usually needs its own permission rather than relying on outbuilding rights.
In Hanslope's conservation areas — including Hanslope and Castlethorpe — a garden building is also judged on its effect on the character of the area, which limits height and footprint before the use question is reached. No residential Article 4 direction applies across the northern villages, so permitted-development rights remain intact outside the conservation areas, while the Hanslope, Castlethorpe, Ravenstone and Stoke Goldington conservation areas protect the historic village cores.
An annexe almost always needs an application to Milton Keynes City Council. Expect one where any of these apply:
We plan the annexe so its relationship to the main house is visible on the page — shared garden, connected access, a layout that reads as one household — and set out the case Milton Keynes City Council has to test, rather than leaving the officer to assume the worst.
Below is Milton Keynes City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Milton Keynes grants most householder applications, but in the northern villages open-countryside policy and conservation-area character are the decisive constraints on new work. Annexe applications are decided on use as much as design, so the supporting case matters as much as the elevations.
Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.
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Across Hanslope, Castlethorpe and Ravenstone, the annexes that succeed keep one shared garden, take access past the main house rather than from the street, and are modest against the host building — single storey where the plot is overlooked, and set back from boundaries. On limestone and brick village cottages and farmhouses, converting an integral garage or a rear ground floor is often approved more readily than a detached garden unit, because the ancillary relationship is self-evident.
The northern parishes lie in open countryside well outside the New Town grid, so extensions and new builds are judged against rural and open-countryside policy in Plan:MK. Where Milton Keynes City Council grants permission, it commonly attaches a condition tying occupation of the annexe to the main dwelling. That condition is not a problem to be avoided — it is usually the mechanism that makes approval possible, and we draft the application on that basis rather than pretending the annexe is something it is not.
We draw annexes across Hanslope. A few of the areas where multigenerational schemes come up most often:
Annexe and granny-flat drawings for Hanslope — a stone-built village and conservation area with the county's tallest church spire — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Annexe and granny-flat drawings for Castlethorpe — a historic village and conservation area beside the West Coast Main Line — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Annexe and granny-flat drawings for Ravenstone — a small limestone village and conservation area to the north — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Annexe and granny-flat drawings for Stoke Goldington — a linear stone village and conservation area on the Northampton road — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Annexe and granny-flat drawings for Gayhurst — a historic estate hamlet with a listed hall near Newport Pagnell — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Annexe and granny-flat drawings for Haversham — a village on the Ouse floodplain north of Wolverton — planned to stay ancillary and drawn to Milton Keynes City Council's policies.
Three similar buildings, three different consents. This is what separates them.
| What you build | Planning status | Key test | What Milton Keynes City Council checks |
|---|---|---|---|
| Garden room, no sleeping space | Often Class E permitted development | Incidental to the house | Height, footprint, boundary position |
| Annexe used by the household | Full application, usually with a tie condition | Ancillary use | Shared garden and access, layout |
| Self-contained unit, own access | New dwelling — full application | Separate planning unit | Policy on new homes, amenity, parking |
| Converted garage or ground floor | Often permitted, use still assessed | Whether use changes | Independence of the accommodation |
| Annexe on designated land | Full application | Designation | Character and appearance |
The ancillary/separate-dwelling distinction comes from section 55 of the Town and Country Planning Act 1990; outbuilding limits from the GPDO 2015, Schedule 2, Part 1, Class E.
A fixed process built around how Milton Keynes City Council tests the use question as well as the design.
Tell us who the annexe is for and where it would sit on the plot. We confirm designation status and tell you honestly whether the scheme reads as ancillary or as a separate dwelling in Hanslope.
We measure the plot, the existing house and the access route, so the shared-garden and shared-access case can be drawn rather than asserted.
Chartered designers develop the annexe to your brief, with the layout, access and garden relationship arranged to support the ancillary case under Milton Keynes City Council's policies.
We submit the application with a supporting statement on use, manage validation and case-officer queries, and revise free until Milton Keynes City Council decides.
Almost always. Sleeping accommodation is generally not "incidental" to the enjoyment of a house, so it falls outside the outbuilding permitted-development right, and any annexe that could function independently raises a change-of-use question under section 55. In Hanslope we prepare a full application to Milton Keynes City Council and make the ancillary case explicitly rather than hoping it is not asked.
A shared garden rather than a divided one, access through the main property rather than a separate street entrance, occupation by a member of the same household, and a physical and functional relationship with the main house. Milton Keynes City Council weighs those together — no single feature decides it, but a separate front door and a fenced-off garden together usually settle it against you. This applies to your Hanslope address specifically.
Yes, subject to permission. A detached garden annexe is assessed on its scale against the plot, its effect on neighbours and the character of the area, and then on the use question. Keeping it single storey, set in from boundaries and served off the shared garden gives it the best prospect in Hanslope, particularly near designated areas such as Hanslope and Castlethorpe. Milton Keynes City Council is the decision-maker.
Commonly, yes — a condition tying occupation of the annexe to the main dwelling, so it cannot be sold or let separately. That is normally what makes approval possible, because it removes the concern that a new independent home is being created without going through housing policy. The condition runs with the land, so it matters at resale, and we explain the implications before you commit. This applies to your Hanslope address specifically. Milton Keynes City Council is the decision-maker.
Yes. A new annexe is new habitable accommodation, so structure, fire escape, insulation and ventilation all apply, and a detached annexe close to a boundary raises fire-spread requirements as well. Planning and building control are separate consents with separate submissions — we prepare both so the approved design is the one that can actually be built. This applies to your Hanslope address specifically. Milton Keynes City Council is the decision-maker.
A householder application runs to an eight-week statutory target; where the council treats the annexe as creating a new unit it becomes a minor application with a thirteen-week target instead. Which route applies depends on how the use is characterised, which is precisely why the ancillary case is worth making properly at the outset. This applies to your Hanslope address specifically. Milton Keynes City Council is the decision-maker.
We quote each Hanslope annexe individually, because plot, access and whether you are converting or building new all change the work, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack and supporting statement, with free revisions until Milton Keynes City Council approves. Call 020 7864 7245 to start.
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