The 2016 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 on 4 November 2016 of the Conservative member of parliament (MP) Stephen Phillips, who left Parliament 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% of the vote, a sizable majority. The Conservatives' vote share fell slightly compared to the result at the previous general election in 2015.