More than a quarter of known labour suppliers to food and drink processors and packers had failed to apply for a mandatory gangmasters' licence a week before the September 1 deadline.
Paul Whitehouse, chairman of the Gangmasters Licensing Authority, said it would use its powers to shut down any business that had not applied for a licence and was still operating a month from that date. "We will stop them and prosecute them, even if it halts production in the processing plant or pack house," he said.
It will also be a criminal offence - punishable by a prison sentence of up to 51 weeks and a fine - for a processor or packer to use labour from an unlicensed gangmaster after December 1. As Food Manufacture went to press, though, there were still 300 of the government-estimated 1,000 labour providers left to apply for a gangmasters' licence, leaving many businesses at risk of operating outside the law, claimed the GLA.
A clampdown would inevitably lead to labour problems in factories and on farms across the UK and if - as some experts have suggested - there are more than 1,000 labour providers, shortages could be even worse.
"If labour providers are not licensed, this could lead in the worst case scenario to production and supply problems in the food industry," said the GLA chief executive Mike Wilson.
The GLA had pledged that applicants which scraped in before the deadline would be allowed to operate beyond October 1, while their licences were processed.
A list of licensed providers is available on the GLA website: http://www.gla.gov.uk.