(BBC) – A mother and son from the West Midlands have admitted arranging “sham” marriages for foreign nationals, mainly from Africa and Jamaica.

Patricia Williams, 60, and Jason Williams, 38, of St John’s Road, Dudley, pleaded guilty to breaching immigration laws.

Last month, seven people who were related to the pair were sentenced for similar offences. The pair will be sentenced at Birmingham Crown Court on 4 September.

West Midlands Police Major Investigations Unit unearthed the scam during covert surveillance of the marriages.

The unit’s work revealed a network of people organising sham marriages and the pair’s guilty pleas come after seven members of the same family earlier pleaded guilty to similar offences.

David, 32, Brett, 31, Daniel, 28, Natalie, 26, and Luke, 24, all from Dudley, were sentenced on 19 June to between 12 and 24 months in prison, after admitting facilitating a breach of immigration laws. Amanda Williams, 35, from Rowley Regis, West Midlands, was given a 12-month suspended sentence and 100 hours’ unpaid work.

West Midlands Police said the six were all involved in sham marriages, between 2004 and 2006, and were paid in cash and drugs for their participation.

And Donna Williams, a 37-year-old Jamaican national from Handsworth, Birmingham, who married Daniel, was jailed for 15 months. Another woman, Dawn Whitehouse, 33, from Dudley, was given a 12-month suspended sentence and two-year supervision order after admitting possession of a counterfeit driving licence.