A draft masterplan for hundreds of homes and business development in Newmarket has been given the backing of senior town leaders.

The controversial development for the Hatchfield Farm site has been allocated in the local plan for use as 400 homes, a primary school, and five hectares of land for business use.

While a formal planning application was submitted in October 2013, which was subsequently approved, the decision has not been resolved because it was called in by then-environment secretary Sajid Javid.

The planning inquiry is to take place from May 8.

Tuesday night’s meeting of the joint executive, comprising cabinet members from Forest Heath and St Edmundsbury councils, backed the masterplan for the area and will now become informal planning guidance as the scheme progresses.

Councillor Lance Stanbury, portfolio holder for planning and growth at Forest Heath, said it did not affect the upcoming planning inquiry.

“The masterplan is designed to be a guide and strategy for developing the site, how the design captures the characteristics of Newmarket,” he said.

Councillor David Bowman added: “I think it will be good overall for Newmarket if and when it goes forward.”

But the plans have sparked fierce opposition from the horseracing community, who fear it will result in traffic increasing.

Wiliam Gittus of the Newmarket Horsemen’s Group, which represents the industry in the area, said: “The masterplan is about making the Hatchfield Farm scheme fit the, as yet, un-adopted local plan.

“It is the impact of the potential scheme on the town which concerns the Newmarket Horsemen’s Group.

“We have provided evidence which proves there is queuing, and which shows that Newmarket will grind to a complete standstill during the peak hours.”

A spokesman from the project team said: ““We continue to believe that 400 homes along with significant improvements to the road network, major investment in the Rayes Lane horse crossing and the provision of land for a new school is an appropriate and sustainable development on this site.”