Polygamy.

"Husbands living in a "harem" with multiple wives have been cleared to claim state benefits for all their different partners.
A Muslim man with four spouses - which is permitted under Islamic law - could receive £10,000 a year in income support alone.
He could also be entitled to more generous housing and council tax benefit, to reflect the fact his household needs a bigger property."
It is a long time since I used the expression. It must now be dusted off as

"THE LUNATICS REALLY HAVE TAKEN OVER THE ASYLUM!