Bereaved relatives want answers about the deaths

Geraldine Smith warned the Home Office last year about the risks to migrant cocklers in Lancashire.

But it said it could not get involved in a police operation on the beaches, because of "resource issues".

Police are still investigating the tragedy after bailing all seven people arrested on suspicion of manslaughter.

A Buddhist prayer service, held by 15 local monks, took place on Thursday for the 19 who drowned.

Ms Smith wrote to the Home Office on 28 June 2003 to describe the plight of migrant workers, and urge the Immigration Service to intervene.

The MP said: "Unable to speak English and under the control of a gang master, these people were being paid one-fifth of the standard rate for their work.

Unable to speak English and under the control of a gang master, these people were being paid one fifth of the standard rate for their work Geraldine Smith MP, in a 2003 letter to the Home Office Home Office 'warned of cockler dangers'

"They were also being transported 20 to a boat in waters renowned for their currents and quicksands, where an experienced local fisherman would not consider carrying more than six."

But Home Office Minister Fiona Mactaggart replied, saying "resource issues" meant there was little point in the Immigration Service intervening.

She cited the difficulties with dealing with the Chinese authorities, the gang masters and the migrants themselves, as circumstances which meant there was "little useful purpose" in sending immigration officials to help the police trying to deal with the issue.

'Problems not missed'

The Home Office later said in a statement that the correspondence had referred to one specific incident, and was "not indicative" of a general lack of co-operation.

Home Office Minister Hazel Blears told BBC Radio 4's Today programme: "I do not accept that things have been missed after warnings given.

"I think the position there is that there has been a problem with this community and with the cockling operations that have gone on.

"As I understand it, there was a police operation involving the Department of Work and Pensions last year and then there was an immigration operation in August last year as well.

"But this community is difficult to protect sometimes. There are forces with the community that mean people are threatened and intimidated."

'No resources'

Three male and two female survivors of the tragedy, arrested on Sunday on suspicion of manslaughter, were released on bail on Wednesday night.

A spokesperson for Lancashire Police said the three men were now in the custody of the Immigration Service.

A local MP had written to the Home Office about the dangers to migrant workers

Two fishing bosses, who said they were also arrested but later bailed, issued a statement through their solicitor denying responsibility for the deaths.

David Eden and his son, also called David, who run the Liverpool Bay Fishing Company, said they had volunteered to speak to the police as they thought they might have information useful to the inquiry.

Many of the dead have still not been identified, and police say it could take weeks or months before they do so.

The family of one man understood to be a victim, Guo Binglong, 30, have spoken from their village in China's Fujian province.

They said he had paid $30,000 (�20,000) for his passage to England, and described how he called them on his mobile while the water rose around him.

Police number for witnesses or those with information - 01524 63333