The Conservatives are heading for a potentially catastrophic defeat in the Wakefield byelection amid reports Boris Johnson could face a vote on his future next week, according to a new poll. A survey by JL Partners and reported in the Sunday Times gives Labour a 20-point lead over the Tories in the Yorkshire constituency. The poll puts Labour on 48% and the Tories on 28%, down by 19 points. The prime minister secured his majority of about 80 seats at the 2019 general election via the so-called Red Wall traditionally Labour-supporting areas in the north of England, the Midlands and Wales which voted Tory. Before the 2019 result, Wakefield had consistently voted for a Labour candidate since the 1930s. Wakefield is scheduled to go to the polls on 23 June to elect a new MP after former Tory incumbent Imran Ahmad Khan was found guilty in April of sexually assaulting a boy. James Johnson, co-founder of JL Partners and a former Downing Street pollster during Theresa May’s tenure, said the Conservatives are “behind Labour in every age group apart from the over-65s”, with polling day less than three weeks away. The polling expert said the primary reason swing voters in Wakefield chose Sir Keir Starmer’s party as their preference was that “Boris Johnson tried to cover up partygate, and lied to the public”. The second most popular reason was because they viewed Johnson as being out of touch with the working class. The result could increase the pressure on the prime minister, who faces a second test in the Tiverton and Honiton byelection on the same day as Wakefield. Almost 30 Tory MPs have publicly called for Johnson to resign over his conduct over the social gatherings during lockdown and the alcohol culture at Downing Street. Under Conservative party rules, if 54 letters of no confidence in his premiership are submitted to Sir Graham Brady, the chair of the 1922 Committee of backbench Tories, then a leadership vote will be held. The Sunday Times said it had been told by one rebel they had privately tallied that 67 letters had gone in during the secret process which would mean the threshold has been reached. According to the newspaper, a vote on the future of Johnson’s premiership could take place as soon as Wednesday. The rebels would need 180 voters to remove the Tory leader from power, otherwise affording him, by the current rules, a year’s stay of execution before another bid to replace him can be held. Meanwhile, Johnson faced further embarrassment on Saturday evening when comedian Lee Mack made a joke about partygate during the Platinum Party at the Palace concert with the prime minister sitting in the royal box. Mack said: “Finally we can say the words ‘party’ and ‘gate’ and it’s a positive” which prompted cheers and laughs from the audience.