Frequently Asked Questions — Ynys Môn Constituency

Who won the Ynys Môn constituency election in 2017?

Labour gained Ynys Môn constituency at the 8 June 2017 General Election, taking the seat from Conservative. Labour won with a majority of 5,259 votes (14.1%). Turnout was 70.6%.

What was the swing in Ynys Môn at the 2017 election?

The swing in Ynys Môn was 9.7% from CON to LAB — a significant shift towards LAB. Swing is calculated using the Butler two-party formula: the average of the change in winner's vote share and the fall in the runner-up's vote share compared to the previous election here.

What does swing mean in UK elections?

Swing measures how much support has shifted between two parties compared to a previous election. The Butler swing formula — used in British election reporting since the 1950s — takes the average of the gain in the winner's vote share and the loss in the runner-up's. A 5% swing is considered large at ward level; anything above 10% is exceptional. The swing figure for Ynys Môn in 2017 is shown in the statistics above.