A by-election for the House of Commons constituency of Sleaford and North Hykeham in Lincolnshire, England, was held on 8 December 2016. It was triggered by the resignation of the Conservative member of parliament (MP) Stephen Phillips, who left Parliament on 4 November 2016 due to policy differences with the Conservative government led by the prime minister, Theresa May, over Brexit – the British withdrawal from the European Union (EU). The Conservatives nominated Caroline Johnson, a paediatrician, to replace Phillips; she won the by-election with more than 50 per cent of the vote, a sizable majority. The Conservatives' vote share fell slightly compared to the result at the previous general election in 2015.