OWNERS of a North-East factory site transformed in part by mobile phone giant Orange remain tight-lipped over a possible new £2.5m office development.

Property developer Highpoint Estates bought the Cummins engine component factory in Yarm Road, Darlington, last year.

It then secured a deal with Orange to take on a major slice of the site for a new call centre which has created hundreds of jobs.

Now the Harrogate-based developer is applying for planning permission to convert an estimated 50,000sq ft of remaining storage space into offices.

Last October The Northern Echo revealed how Highpoint was in talks with several potential tenants for the factory space and 15 acres of nearby development land, which has been earmarked for a new business park.

Plans for a health and leisure club were mooted, but have so far failed to come to fruition, while insurance company AXA - which has an existing call centre in Darlington - has also been linked with the site.

Dmytro Chervak, chairman of Highpoint, said it would be premature to say who could move into the office development, if it gained planning permission.

However he added: "This is probably the single most important building in the town and it is only logical that we are approaching the main employees already here to see whether they have plans to expand."

Highpoint says the plans to convert the remaining factory space, which include a parking area for 200 cars, represent phase two of its investment plans.

It has already spent more than £3m on the Grade II listed building in refurbishment work.

A spokeswoman for AXA said the lease on its call centre expired on 2002.

However she refused to say whether it was looking to move to the Yarm Road site.

She said: "We have been looking at alternatives to our current site but no decision has been made to move so far."