An undercover investigation by Hillside Animal Sanctuary filmed workers at Hall Farm in Hingham, Norfolk, picking up live birds and swinging them around by their necks before flinging them across a farmyard floor, according to Supply Management.

The farm, which rears ducks under the Gressingham duck range for the supermarket, is run by Green Label Foods.

The ducks are sent to Gressingham Foods to be processed before being delivered to Waitrose supermarkets around the country.

In a statement, Waitrose said: "We are appalled by the footage taken at Hall Farm and as soon as we saw it we suspended the supplier while we carry out a full investigation. We immediately sent a vet to the site to ensure the welfare of ducks remaining at the farm and [we] are staying very close to the situation. This kind of behaviour is totally unacceptable and completely goes against the high welfare standards Waitrose expects of its farmers."

Green Label Farms, who contracts the team of catchers shown in the undercover video, has suspended all those involved while it undertakes its own investigation.