Durham is testing whether the NETPark model can be repeated in Durham City.

County Hall, the council’s headquarters since 1963, is expected to be demolished in 2027 to clear the Aykley Heads site for up to 400,000 sq ft of office, research and workspace.

Durham has already run the experiment once, thirteen miles away in Sedgefield. It is now applying the same approach in the city, with the council’s own headquarters at the centre of the scheme.

When County Hall was officially opened by Prince Philip, the Duke of Edinburgh, on 14 October 1963, it came with its own barber, bank, shop, bar and a silver-service restaurant for councillors.

Durham County Council chair Robbie Rodiss marked the building’s closure in August 2026. He said the barber, bank, shop, bar and silver-service restaurant had long gone but “the sense of community has remained”. The building had held “many lively debates and key decisions”, “countless friendships” and “the odd romance or two” across 63 years.

NETPark, the council's science park built on a derelict hospital site from 2001, took two decades to prove a public body could grow companies rather than just attract them. Kromek, a Durham University spin-out, arrived with three staff in 2004 and is now listed on London's AIM market. Filtronic and SEEDS both grew past the point where they could have left for somewhere bigger and chose to build on-site instead. Durham is now trying to bring that approach to the city, with the council’s headquarters at the centre of the scheme.

Aykley Heads is the site. Durham Innovation District is the development brand. The Durham Mayoral Development Zone is the funding designation attached to the site in March 2026, with £27m in associated funding. The names are often used interchangeably, but they describe different things: a location, a development and a funding mechanism.

Durham Cabinet decided in September 2021 that refurbishing or partially demolishing County Hall did not represent value for money and that the building should come down entirely to make way for the Durham Innovation District on the Aykley Heads site. Staff and councillors left the building in August 2026.

Rivergreen, a separate building on the same site, was converted from offices to mixed civic and office use under planning approval granted in February 2025 and is now the council's working headquarters.

The council marked the closure with a public open day, exhibiting original 1963 architect's drawings and footage from the building's opening. Demolition is expected in 2027, though the date and cost are not yet confirmed.

The site's planning history predates the innovation district branding and shows how the scheme has evolved since its original conception. Durham secured planning permission for the Aykley Heads site in January 2021 through a hybrid consent: detailed permission for one office plot and outline permission for the rest of the site, including the demolition of County Hall. The approved scheme covered almost 40,000 sq m of floorspace, almost entirely offices, and was described throughout the application as a business park.

That changed in September 2023, when Durham Cabinet approved an outline business case and the procurement of a joint venture partner. The business case explicitly repositioned the scheme from business park to innovation district, citing shrinking office footprints and stronger demand for higher-quality, amenity-rich space, reflecting the shift in occupier demand since 2020. The planning consent stayed the same. The council changed the proposition to reflect what NETPark had taught it about the market.

NETPark was built and is still run directly by the council through its development arm, Business Durham. It grew tenant by tenant over two decades. The Durham Innovation District is delivered at Aykley Heads through a formal 50:50 joint venture with a national developer, brought in through competitive procurement rather than managed in-house, on a timeline measured in months rather than years.

Through the procurement process, Durham awarded the contract to Muse Places Ltd, a UK regeneration developer. Durham County Council and Muse incorporated the joint venture, Aykley Heads Development LLP, shortly afterwards.

The council's 2023 business case envisaged a 15-to-25-year partnership and a 50:50 split if council land and infrastructure were matched by equivalent partner investment. The final commercial terms, including the profit split and risk allocation, have not been published.

Public funding followed within a year of the joint venture being signed. The regional mayoral authority, led by North East Mayor Kim McGuinness, committed £27m towards the project.

NETPark's first tenant was Kromek, a Durham University spin-out. Durham University is the first confirmed major anchor for the Durham Innovation District. The Durham City Incubator, which supports university spin-outs and high-growth start-ups, is already based at Aykley Heads. The university's data centre is the only part of the wider scheme to have received detailed planning approval so far. It includes ancillary office space on Plot D and was approved in January 2025. The university's planning statement puts the investment at around £250m.

The university and Muse signed a further collaboration agreement with the council in October 2025, though its terms have not been made public. The university's data centre and the council's own move into part of the site are the only other confirmed occupancies, and no private business has been named publicly for the wider workspace.

Aykley Heads has been described with several different floorspace figures, reflecting different stages of the scheme. The original 2021 consent covers 38,468 sq m, about 414,000 sq ft. The 2023 business case gave a smaller deliverable figure, up to 382,000 sq ft, depending on land assumptions around Rivergreen and Plot E. The 2025 procurement notice rounded the scheme to 39,000 sq m and up to 4,000 jobs. A 2025 variation tied to the university's data centre lifted the total again, to about 39,500 sq m. The figure now used publicly, "around 400,000 sq ft", sits close to all of them without matching any exactly.

The public funding has also been announced in stages, with figures attached to different parts of the scheme. The mayoral authority's £27m in March 2026 came with a further £12m for site-wide infrastructure and up to £15m of indicative capital funding for the first phase, a material part of which is expected to be repaid.

Durham's own medium-term financial plan separately lists £3.484m for active travel routes on the site and £1.016m in programme development costs. Much of the support is structured to be repaid rather than provided as grant funding.

NETPark took most of two decades to prove its model, growing tenants slowly until Kromek, Filtronic and SEEDS demonstrated that companies could grow and stay on site. Aykley Heads is on a shorter timetable.

The council expects to demolish County Hall in 2027 whether private tenants have signed by then. The council and a university-led data centre are the two confirmed occupiers for the wider development. No private tenant has been named for the remaining workspace, so the scheme still has to attract businesses rather than simply move existing public occupiers. Place North East, the property trade publication, reported that the district is being pitched at data science, fintech, green technology and healthcare businesses.

Comparable public-led innovation buildings elsewhere have produced contrasting results. Newcastle Helix filled two buildings faster than expected: The Catalyst building reached full capacity around two years after opening, and The Spark building was fully let by February 2026.

Liverpool's Paddington Village offers a counterexample. The Spine, its flagship building, still had more than 70,000 sq ft unlet two years after opening, despite the Royal College of Physicians as anchor tenant.

The Durham Innovation District has one confirmed anchor, public-sector financial support and a proven local precedent behind it. The test is whether it can attract enough private occupiers to replicate NETPark's tenant growth.

What is Durham Innovation District? The branding for a roughly 400,000 sq ft office, research and innovation scheme planned for the Aykley Heads site in Durham City, on land currently occupied by County Hall.

Who owns the site? Durham County Council, which has contributed the land to a joint venture with developer Muse Places Ltd.

Who is delivering it? Muse Places Ltd, through a joint venture vehicle, Aykley Heads Development LLP, incorporated in April 2025. Durham University is a separate collaboration partner, not a joint venture member, and is delivering its own data centre on the site.

When does County Hall come down? Staff and councillors left the building in August 2026. Demolition is expected in 2027, though the council has not confirmed the demolition date or cost.

Is there a confirmed occupier yet? Existing activity includes the Durham City Incubator. Durham County Council itself and Durham University's data centre are the two confirmed occupiers for the wider development. No private business has been named publicly for the rest of the space.

As of August 2026, no application had yet been submitted for detailed planning approval for the remaining workspace. County Hall is expected to come down in 2027, before any private occupier has been named. Durham has committed its land, its headquarters and public-sector financial support to the proposition. The private-occupier test still lies ahead.