London, Dec 14 : British Prime Minister Rishi Sunak net favourability rating slipped to 'worst ever' amid the controversial Rwanda policy row, with a new poll showing 70 per cent of people holding an unfavourable view of the leader. Only 21 per cent had a favourable opinion of him, according to a YouGov poll conducted just before Sunak won the crucial vote on the Rwanda bill. "This gives the Prime Minister his lowest ever net favourability score of -49 -- a 10 point drop from late November," the poll said, adding that the present Prime Minister is now as unpopular as Boris Johnson in his final days in office. At the time of Johnson's resignation, YouGov recorded a low of -53 for the former Prime Minister, although still not as bad as Liz Truss's -70. Similarly, 2019 Conservative voters revealed a more negative view of the leader of the party they backed four years ago, in another new low for the Prime Minister. A recorded 56 per cent expressed a negative opinion, while 40 per cent shared a positive view with pollsters. Meanwhile, Sunak got some respite on Tuesday as the House of Commons voted 313-269 to approve the government's Rwanda bill in principle, sending it on for further scrutiny. The Rwanda plan, agreed by then Prime Minister Boris Johnson in 2022, seeks to deter migrants from making the perilous journey of about 32 km across the Channel in small boats or inflatable dinghies. Under the plan, anyone who arrived in Britain illegally after January 1, 2022, faced being sent to Rwanda, some 6,400 km away. The first deportation flight in June 2022 was blocked by a last-minute injunction from the European Court of Human Rights. The plan is of utmost importance to Sunak as he made "stopping the boats" one of his top five priorities after he became the Prime Minister. /IANS