William Legge, 10th Earl of Dartmouth, (born 23 September 1949), styled Viscount Lewisham from 1962 to 1997, is a British politician and hereditary peer, usually known as William Dartmouth.
Dartmouth sat in the European Parliament as an MEP representing the South West England between 2009 and 2019.
He was elected for the UK Independence Party (UKIP) and served as national spokesman on trade from 2010 to 2018.
He resigned from UKIP in 2018 due to his dissatisfaction with the UKIP Leader, Gerard Batten.