Some Muslim Britons contract an Islamic marriage (but not a civil one) and then fail to confer on the bride the marriage settlement that would be obligatory in say, Pakistan.

ECONOMIST: Sharia in the West

Mr Crabb added that during the 12 months that he claimed additional costs allowance (ACA) against this property he, along with all the freeholders on the estate, paid for "obligatory external paintwork to be done", and for five new windows following a burglary at the flat.

BBC: Stephen Crabb MP

An alternative would be to make natural-disaster insurance (covering floods, earthquakes, avalanches and so on) obligatory, with premiums more closely reflecting the risk.

ECONOMIST: Hurricane Katrina