Any archaeological finds made during the preparatory work to put up a new warehouse on the edge of Swindon must be properly protected and looked after.

Developer Tritax Symmetry, which owns and manages Symmetry Park just off the A420 in Gablecross already has planning permission to build warehouses on the site, which it has done and is doing.

It now wants to develop the rest of the site and made an application to be able to do so without submitting the archaeological management plan that it did for the rest of the site earlier.

It submitted an environmental statement where it said any likely finds on the undeveloped portion of the park, now called plot three would be unlikely to be important: “The known archaeological remains that survive buried within the site are not designated; they are considered by Historic England to be of insufficient significance to be scheduled.

“They are not protected from physical alteration under statute or afforded the highest level of policy protection. They are considered non-designated heritage assets.”

But the application was refused by planners at Swindon Borough Council who said: “The proposal would result in the loss of significant archaeological remains which are to be preserved in situ.

“The harm to the remains would represent substantial harm and no clear or convincing justification has been provided for this. As the application has not demonstrated that the substantial harm or total loss is necessary, the public benefits of the proposal do not outweigh the harm or loss and are entirely uncertain in any event.”

Tritax Symmetry appealed to the Planning Inspectorate against this decision, and the appeal was heard by the government-appointed inspector Beverley Wilder in December, with a visit to the site in January.

The inspector dismissed the appeal saying: “I consider that the evidence that is available at present indicates that plot three retains reasonable archaeological potential. As such it is deemed to have national importance.

“Plot three is the likely location of a Roman settlement with some small industrial works. Further investigations would be useful, but I am satisfied, the required archaeological potential has been demonstrated.”

Tritax Symmetry also appealed to the inspector for a decision on its plan for Plot three, which would see a new warehouse built nearest the roundabout on Laines Way, as the borough council’s planners had missed the deadline for their decision.

But the inspector found against the developer on grounds of the impact of the building on protected species which live on the site and also the impact on the Grade II-listed lock keeper’s cottage just to the east of the site.