"Islamic law permits men to have up to four wives at any one time - known as a harem - provided the husband spends [arranges for British citizens to provide the resources so that he can spend] equal amounts of time and money on each of them."
[My corrections]
A desperately, passionately depressing article; but essential and relevant, thank you.
This FR thread from April may also be of interest:
Great Britain Muslim is spared a speeding ban so he can drive between his two wives