 Maslin had won the seat in May 2016.Byatt had represented Westham on W&PBC and DCC before as well as being the labour leader on W&PBC but switched the Conservatives in 2016

Green councillor Claudia Moore (Weymouth West) resigned from the council on 20 December 2017.She was elected in 2014 and the vacancy was originally going to be left to be filled in the scheduled on-third election on 3 May 2018.