Kemi Badenoch is to pledge that a future Conservative government would end benefits for polygamous households, arguing that the welfare system should not provide additional payments for relationships that are illegal in Britain.
The proposal, due to be put before Parliament on Tuesday by the Conservative leader and Tory MP Richard Holden, would prevent extra money being paid for multiple spouses. Labour is expected not to support the plan.
Polygamy is prohibited in the UK, but marriages conducted overseas can be recognised by the welfare system where they were lawful in the country in which they took place. This means additional spouses may qualify for payments on top of the standard couple rate.
For pensioners, each spouse claiming benefits can receive £125.25 a week in pension credit and a further £125.25 in housing benefit. A household comprising one husband and four wives could therefore receive £1,504.40 a week in the two benefits, equivalent to £78,229 a year.
That is £39,406 more than the maximum available to a typical couple, according to the figures cited in the proposal. There is currently no limit on the number of spouses who can be claimed for, meaning a household with 11 wives could receive £170,175.
Government sources have insisted that people do not profit from polygamy. However, the Conservatives argue that the current arrangements amount to the welfare system rewarding a practice that is unlawful in Britain.
Mr Holden, who is also campaigning to ban cousin marriage, said: “Taxpayers… will be furious that they are supporting relationships of men to multiple wives.”
He added: “Our welfare system should not reward damaging cultural practices that are rightly illegal. My Bill would scrap this outrageous arrangement.”
Marrying multiple wives has been a crime in Britain for 400 years, although such marriages can be recognised when they were lawful in the country where they took place. Polygamy is fully or partially legal in 58 countries, mainly in the Middle East, Africa and parts of Asia.
The Conservative proposal would also restrict benefits for people in incestuous unions and cousin marriages. Analysis cited in support of the move found that benefits were a quarter higher in areas where cousin marriage was more common.
In Bradford, where one in six people are born to parents who are cousins, disability benefits were said to be 23 per cent above average. Experts attributed that difference to the risk of birth defects when parents are closely related.
A Department for Work and Pensions spokesman said there were very few claimants from polygamous households. He added that immigration rules had “generally prevented the formation of polygamous households in this country since 1988”.
