He became prime minister in 1990, but was dismissed in 1993, clearing the way for the then opposition leader, Benazir Bhutto, to form a government.

BBC: Profile: Nawaz Sharif

But two copies of the "met" form produce a weaker version of COMT that is not so good at clearing away the chemicals.

BBC: Gene controls pain threshold

Lewis was in good form throughout the weekend and narrowly missed out on a medal in the pole vault after clearing 5.71m.

BBC: GB end Euros with relay silvers