A farm owner has won planning permission for four units to house pigs on their site despite concerns about the effect of increased traffic on an ancient pathway.

The retrospective application by Watering Farm, near Stow Bedon and Breckles, sought permission for four pig rearing units to house 4,600 pigs.

While the application raised concerns about increased agricultural traffic to the site, which is accessed via the 2,000-year-old Peddars Way, Breckland Council's planning committee believed it would be better environmentally for the pigs to be kept inside and so allowed the buildings to stay.

However, the approved application states that all pigs currently being kept outdoors – around 9,000 – must be removed and the farm's overall number of animals must stay below 7,000.

Strong objections were raised by parish councils including Stow Bedon and Breckles, Wretham and Great Hockham. Norfolk Wildlife Trust and the RSPB had also objected.

Julian Gibson, clerk for Stow Bedon and Breckles, said: 'My council did everything it could to get Breckland to refuse the application, but they were not successful.'

Philip Cowen, Breckland councillor for All Saints and Wayland, said communities around the Peddars Way had seen a 'considerable fall off' in walkers using the route since the units were built at Watering Farm and agricultural traffic increased.

'The Peddars Way has been completely changed,' he said. 'If your business is accessing its site via an ancient pathway, it brings with it different responsibilities.'

He said the decision to limit the number of pigs the farm could keep would bring vehicle movements on the Roman track down from 9,000 per year to 1,100, adding: 'We had to find a way to protect an asset which runs through our district.'

Traditional Norfolk Poultry is also accessed by the Peddars Way and has been accused of contributing to its erosion. The farm had a retrospective application for three poly-tunnels refused by Breckland Council in 2013.