British police have carried out raids on properties across the northwest of England as part of a search for the labour agents of 19 mainly Chinese migrants who drowned on a beach last week while gathering shellfish.
Yesterday, detectives said they expected to make arrests within days and were searching for the people to whom the 19 low-wage workers were sent to gather cockles in Morecambe Bay, Lancashire, where they were engulfed by the rising tides of the Irish Sea on Thursday.
The tragedy has led calls for laws to be tightened in the murky world of gang labour, where so-called gangmasters farm out migrant labourers, often illegally, to do poorly paid jobs in agriculture and unskilled industrial work like construction.
The young victims, 17 men and two women, were cut off in bitterly cold weather by rising tides in the treacherous flat bay, where the water rushes in faster than a person can run.
Police said some of them tore off their clothes to swim more easily and held hands in a desperate attempt to stay afloat.
Detectives said they had carried out a number of raids as they chased leads in the Merseyside area.
Earlier yesterday Detective Superintendent Mick Gradwell told reporters he had a large number of names of gangmasters.
"We are narrowing that list down as to the people who might be involved in this incident," he said. "I would suggest that arrests are likely to be in days rather than weeks."
Thge Bishop of Lancaster Patrick O'Donoghue said self-regulation by the employers had failed. "The government must step in and set down legislation," he said.
Gangmasters said they would welcome a register and better regulation.
"We provide labour to the lower wage industry. I think indigenous, English folk don't want to do a lot of these jobs," one gangmaster told the BBC.
The government said the bay holds more than six million pounds worth of cockles.
Immigration has become one of the hottest political issues, fuelled by media reports of large numbers of asylum seekers supposedly "milking" state benefits.