uk prime minister theresa may conservative party lead poll first time since june election accord yougov poll time theresa may advantage labour party jeremy corbyn double newspaper say yougov poll conduct sunday monday among 1,680 adults suggest may brexit deal appear improve public stand push tories ahead 42 per cent labour 41 per cent vote liberal democrats per cent rest 10 per cent time say public still think government good job brexit theresa may prefer choice best prime minister 37 percent vote 28 percent vote jeremy corbyn paper add public shift view referendum 44 percent say britain right vote leave 45 per cent say wrong choice tories lead first time since june election time