LONDON (Reuters) – Britain’s opposition Labour Party has extended its lead over Prime Minister Liz Truss’s Conservative Party to 19 points, an opinion poll by market research company Opinium showed on Saturday, on the eve of the Conservatives’ annual conference. Opinium’s is the latest in a series of polls to show a growing Labour lead after investors baulked at unfunded tax cuts in finance minister Kwasi Kwarteng’s Sept. 23 fiscal statement, forcing the Bank of England to step in to stabilise markets. The Opinium poll, based on a survey of 2,000 British adults between Sept. 28 and 30, showed …