Home Office officials were alerted eight months ago to the issue of Chinese cockle pickers in Morecambe Bay.
But they said the immigration service had higher priorities since the workers were difficult to remove from the UK and would never testify against their gangmasters.
Geraldine Smith, the MP for Morecambe and Lunesdale, wrote to Beverley Hughes, the Home Office minister, in June after immigration service officials failed to attend a combined raid by police and the Department for Work and Pensions on cocklers at Pilling Sands, five miles from where 19 people died last Thursday.
In a letter of reply, received on 8 August seen by The Independent, Fiona Mactaggart, the Immigration minister, said that the raids could result in the arrest of unscrupulous gangmasters, but said the immigration service had greater priorities.
Ms Mactaggart said many Chinese immigrants arrested in previous raids had been in the UK unlawfully but "few if any had been removable" because the process of obtaining passports from the Chinese authorities proved "time-consuming and often unsuccessful".
She said: "As with most organisations there are resource issues. The immigration service has more requests for its assistance than [it] can service."
Ms Smith said that the service's failure to support operations to tackle the cocklers meant that police had been unable to interview Chinese cocklers or gangmasters. "Morecambe [has] all the usual socio-economic challenges and the police have a lot to deal with. They did not get the support they deserve," she said.
Lancaster City Council said yesterday that the problem of Chinese cocklers packing into houses had been evident to the authorities last August. After discovering 30 Chinese were living in several homes, the council served overcrowding notices on three houses in Morecambe, leading to the Chinese tenants moving out. They moved to another address in Morecambe where further overcrowding notices were served but ignored. A warrant for possession of the house was to have been executed on 18 February.
Ian Barker, the council leader, said yesterday: "We have been involved in addressing housing and social issues that the influx of Chinese cocklers have presented to the district. The immigration service seemed overwhelmed."
Eight of the 19 dead cocklers have been identified but detectives said they could not confirm that one of them was Guo Binlong, 29, who reportedly used his mobile phone to call his wife 5,000 miles away in the village of Zelang, near Fuqing City, as the waters rose. He is reported to have told her: "I am up to my chest in water. Maybe I am going to die. It's a tiny mistake by my boss. He should have called us back an hour ago."
Two fishing company managers arrested and bailed on suspicion of manslaughter in the case denied responsibility.
Speaking through their solicitor, David Eden, 60, and his son, also David, who run the Liverpool Bay Fishing Company, declined to say whether they had bought cockles from Chinese workers but said that there was "no suggestion" that they acted as gangmasters.Reuse content