Gangmasters have accused their customers in the fresh produce sector of tacitly endorsing the exploitation of workers by paying labour providers too little.
The Association of Labour Providers chose the first anniversary of the Gangmaster Licensing Act on 1 October to point the finger at retailers, growers and packhouses. The ALP said the situation had been made worse by the 17p rise in the national minimum wag to £5.52 and an increase in holiday entitlements from 20 days to 24.
"Our members have reported that many labour users are refusing to pay the full increase in rates to labour providers," said ALP director David Camp. "It is totally unreasonable."
Supermarkets had to share responsibility for cases where workers were being exploited, he said. Since the Act came in last year, a number of high-profile investigations have exposed abuses at major packers such as Bomfords.
"Supermarkets and other wholesale purchasers have a duty to ensure they aren't benefiting from exploitation and tax evasion, by paying fair rates to labour providers," Camp added.
Soft fruit grower Hall Hunter, which runs five farms in the south east, said supermarket buyers were too short-termist. "They don't build long-term relations with growers and are happy to take bids based solely on a lower price," said co-director Harry Hall.
The Gangmaster Licensing Authority has drawn up guidelines for labour users on how to ensure they are not exploiting workers.
Defra has calculated that labour providers need to make a margin of 36p per hour its workers are contracted. Reports suggest labour providers are under pressure to reduce this.
But the British Retail Consortium rejected the claim that supermarkets were responsible. "Blaming retailers is an excuse - they're paying suppliers enough," said a spokesman. "If suppliers can't pay the minimum wage, they shouldn't be in business."