The new polling is the latest blow to the Prime Minister as support plunges less than a year after his landslide election win.
Sir Keir Starmer beats only Liz Truss in head-to-head contests against former PMs, new polling shows.
The Prime Minister has a 30-point lead over the former Tory premier in the YouGov research, with 43% saying he is better, compared to 13% opting for Ms Truss.
But Ms Truss, who was in charge for just 49 days following a backlash to her mini-budget, is the only recent occupant of 10 Downing Street that Britons prefer Sir Keir to.
Former Labour PM Sir Tony Blair is 35 points ahead, with 45% saying he was a better PM compared to just one in 10 saying Sir Keir.
Gordon Brown, another ex-Labour premier, has a 30-point lead over Sir Keir at 42% to 12%.
Margaret Thatcher is the Conservative prime minister favoured over Sir Keir by the largest margin.
Some 44% said the Iron Lady performed better, compared to 25% for Sir Keir.
Lord Cameron and Sir John Major are both seen as better in the top job than the Prime Minister, by margins of 41% to 24% and 39% to 16% respectively.
Boris Johnson and Rishi Sunak both have a three-point lead over the Labour politician, although this is within the margin of error.
Some 35% said Mr Johnson – who was ousted over the partygate row – was the better PM, compared to 32% who picked Sir Keir.
Mr Sunak, who lost the general election to Labour, was backed by 33%, while 30% opted for Sir Keir.
Theresa May, who resigned after repeatedly failing to get her Brexit deal through the Commons, has a four-point lead with 32% to Sir Keir’s 28%.
It comes as Labour has seen its poll ratings plunge since its landslide election win last July.
