Decision day has been set for the massive 4,115-home Elms Park development on the outskirts of Cheltenham and Tewkesbury.

Councillors from both areas are due to host two special meetings on May 29 to determine whether the £1billion scheme should be approved.

The project has been more than a decade in the making with Bloor Homes and Persimmon Homes starting work in 2008 and submitting an outline application in 2016.

Planning officers from both areas have spent the last nine years jointly assessing the details and wrangling with the developers over them. Various amendments have been made and the determination date pushed back numerous times, mostly recently to May 30.

The cross-boundary application is now finally set to go before Tewkesbury Borough Council and Cheltenham Borough Council just one day before this expires.

If it is given the green light it would see the largest ever swathe of greenbelt land in the UK transformed into a new town spanning 620 acres. It would stretch from the A4019 Tewkesbury Road to the Hyde river and encompass land in Swindon Village, Uckington and Elmstone Hardwicke.

It would include a mixture of more than 4,000 homes, a 25-acre business park, 100-200-bed hotel, a doctors surgery, sports hub, community centre and three schools.

However, it may still fall at the final hurdle as both committees need to vote to approve the application or the development cannot go ahead.

Tracey Birkinshaw, director of community and economic development at Cheltenham Borough Council, said: "As this is a cross-boundary site it will be considered separately by the planning committees of each council.

"Cheltenham and Tewkesbury, as local planning authorities, have been working collaboratively on this development throughout the journey of this planning application and this includes a shared case officer. As such the officer recommendation and the detail of the report to planning committees will be the same for each council.

"We cannot pre-empt the debate and decisions of the planning committees. Approval of the application requires the approval of both planning committees. If either committee refuses the application, then the applicant will be entitled to appeal."

The land was first earmarked for a mixed development in the Joint Core Strategy between Tewkesbury, Cheltenham and Gloucester councils. It was adopted in 2017 and sets out how they want the region to develop.

Campaigners from Save the Countryside have dedicated hours of their spare time over the years to fighting the loss of so much of the Cotswolds countryside.

Developers claim Elms Park would play a crucial role in the region's future growth with £1billion set to be invested into the construction sector over 10-15 years. They estimate the completed project would bring more than 5,000 jobs and £210million annual income to the area.

The project is also linked to the £293.2m M5 J10 improvement scheme by Gloucestershire County Council which will break ground this summer if given the final green light from the Government.

It would see the area unlocked for future residents with a new link road to west Cheltenham created, widening of the A4019 Tewkesbury Road and provision of dedicated footways and cycle lanes.

Meanwhile work on Elms Park has already begun.

The first phase, a 266-home development known as Regents Village, was approved in March 2023 and is being built off Manor Road in Swindon Village with details of its site levels, street design, tree planting and future road management and maintenance recently submitted.

At the time of the decision some councillors expressed concerns it was putting the cart before the horse but Persimmon Homes said the initial wave of homes would potentially inform the wider Elms Park plans.

If the outline planning application is approved later this month there would still be years of planning work ahead to confirm the finer details of the development.

Tewkesbury Borough Council is due to hold a special planning meeting from 9.30am on Thursday, May 29 to determine the application.

Cheltenham Borough Council is due to hold an Extraordinary planning committee meeting from 3pm on Thursday, May 29 to make its decision.

The Elms Park Consortium said in a joint statement: " The application includes 4,115 new homes with 35% being affordable housing, a modern 10-hectare business park, three new schools (one secondary and two primary), improvements to offsite cycling routes, extensive green infrastructure, a new transport hub with new bus services into central Cheltenham and Tewkesbury, a new sports hub including tennis courts and an all-weather pitch, new community centre and new Doctors surgery.

"There will also be more than 100 hectares of publicly available open space, including a large new park and multiple play areas for younger and older children.

"The proposed development will deliver much-needed housing, and particularly affordable housing, to the region and we hope that the planning committees consider the application favourably."