About 70 jobs are at risk in Harston after the Porsche and Aston Martin garage franchise owner Lancaster failed to win planning approval to build new showrooms in Duxford.

The owner of the dealership in Harston High Street said it risks losing its Porsche franchise if it cannot keep up with the brand's dealership standards, in what was described as a "competitive market".

If the Porsche showroom were to close, the applicant's agent Colin Brown said, the Aston Martin garage may not be able to stay open either, as the two share resources.

Lancaster wants to move to a greenfield site off the A505 in Duxford, on the edge of Whittlesford Bridge.

The proposal was unanimously rejected by the South Cambridgeshire planning committee on Wednesday (June 12).

When making the case for approval Mr Brown said it would be "protecting some 70 jobs".

He said the Harston site is too small with no room for expansion. He said it is "inefficient because there is inadequate space to park and store cars destined for the market. This means that they have to store cars off-site and make numerous round trips". He said: "In this case, Porsche, in particular, has indicated that they no longer wish to continue to supply cars if my clients cannot move to a more suitable site with an appropriate presence close to the existing dealership and fulfilling other requirements."

He said Lancaster has been looking to move for four years, and the search for a new site has been "extensive".

He said: "The site subject to this planning application is the only realistic option that will enable them to remain operational in South Cambridgeshire, protecting some 70 jobs."

He added: "We thought that the council might want to see this facility kept in the district and the jobs that are there retained in the district, so we saw that as quite an important consideration - clearly if you decide not to support this, other things will have to be considered."

The application was recommended for refusal by a planning officer, who concluded: "The proposed development would be located outside of the village development framework and within the open countryside. The proposed site has not been allocated in the local plan, neighbourhood plan, nor is the scale of the development supported by other policies in the local plan."

They said it "would encroach into the current open undeveloped countryside. The proposal would be excessively prominent in its location, resulting in the loss of open, rural countryside and cause harm to the visual amenity of the area".

Summing up the arguments, Councillor Henry Batchelor said: "I think we should give some weight to the fact that there are jobs in South Cambridgeshire at stake here. But on the flip side of that, I do not think in this particular case South Cambs should be giving up their planning policies for the business model of a luxury car company. Other than that though I think there are strong reasons for refusal - objections from a raft of statutory consultees, six parish councils in the area, and the case officer have recommended refusal".

Group property manager for Lancaster, Michael Newton, did not comment on the decision as he left the committee room.