In a setback to UK Prime Minister Theresa May, a eurosceptic lawmaker today registered a massive victory in the by-election in a posh London suburb, indicating a rebuke over the government's plans to pull Britain out of the EU. <br/><br/>Liberal Democrat candidate Sarah Olney, who fought on an anti-Brexit platform, overturned a whopping 23,015 majority of the ruling Conservative party in South West London. <br/><br/>She defeated Zac Goldsmith, by polling 20,510 votes, compared to his 18,638. Goldsmith had held the seat for May's Conservative party since 2010.<br/>In contrast to the rest of the country, London had voted for Remain in the June 23 referendum, with Richmond a strong pro-Remain constituency.