VICTIMS of human trafficking are being used to pick cockles on a part of the coast where it is banned over sewage concerns, it is claimed.

Groups of mainly south-east Asian men, women and children were filmed harvesting large quantities of the clams from the Adur Estuary in Shoreham during an undercover investigation.

Collecting shellfish from the beach is banned because there is a risk of food poisoning with raw sewage being pumped into the river from passing barges. Picking the cockles for commercial gain is illegal but the footage suggests the cockles are being sold for up to £10 a kilo. Authorities believe the people could be the victims of human trafficking, an investigation found. The area is also a Site of Special Scientific Interest so access is restricted to allow habitats to develop naturally.

Fisherman Graham Poulter said he has seen at least 28 people there in one day. Many of the pickers were women in their 20s and there were also children, some of which were believed to be under the age of ten.

Resident Simon Cooper spoke to the pickers but they moved to the other side of the river. He described it as "harvesting" from the river bed on a "huge scale" and claimed he saw large buckets of cockles being loaded into the backs of vans. He said: "It seemed like an organised outfit."

Following the investigation by BBC One's Inside Out programme Sean Ashworth, of Sussex Inshore Fisheries Conservation Authority, also said it looked like commercial activity which would be illegal.

An Adur District Council spokesman said: "We have never found shellfish from the river in any local food establishments during our inspections which are unannounced. The individuals we have spoken to collect them for personal consumption. If we gained proof shellfish were actually being collected for commercial sale and not just for person consumption, then we could instigate court proceedings. If the court found them guilty they could get an unlimited fine and a jail sentence."

The council is planning to put a warning sign in different languages along the shore near the car park.

The trading standards team at West Sussex County Council would be responsible for investigating cockle picking. In 2012 police agreed to track cars of people illegally taking shellfish. Adur council report car registrations to police and the newly formed Food Crime Unit at the Food Standards Agency.

A Sussex Police spokeswoman said the force works with the Marine Management Organisation and Natural England to tackle illegal cockle picking. She said police would also investigate any crimes which could relate to those collecting the cockles.

Cockles are a vital food source for birds and picking them can damage the conservation area's ecosystem.