He's failed to meet key pledges, hit an opinion poll low, and even cramped the style of a popular Adidas shoe: Britain's beleaguered Conservative leader Rishi Sunak appears destined to lose a looming general election.

Two tax cuts and a slightly improving economy have failed to boost Sunak's political fortunes, while criticism from ex-prime minister Boris Johnson and speculation over Brexit figurehead Nigel Farage's intentions are adding to his woes.

Political scientist Rob Ford reckoned Sunak has been left looking "hapless" in the face of seemingly unstoppable political momentum away from his ruling Tories.

"When the herd moves, it moves. There's not much you can do," he told AFP.

Sunak, 43, has yet to announce the date of the election. He is expected to call it for October or November but is legally allowed to wait until January at the latest.

Surveys overwhelmingly show that Britons want an end to 14 years of Tory rule, and nothing that Sunak has done since he became PM 18 months ago appears to be changing their minds.

A YouGov poll released this month found that the Conservatives would win just 155 seats in the UK parliament, down from the 365 that they won under Johnson at the last election in December 2019.

Keir Starmer's opposition Labour Party would win 403 seats, the same survey found, leading to a whopping 154-seat majority.

"Right now, it's very difficult to see how the Conservatives remain in government after the next election simply because of the scale of shift they need," said Keiran Pedley, director of politics at polling firm Ipsos.

- 'Moving the dial' -

Sunak succeeded Liz Truss in October 2022 after Tory MPs forced her out following a disastrous 49 days in office, during which her mini-budget spooked financial markets, sank the pound and sent mortgage payments skywards.

She had followed Johnson, who himself had been defenestrated by colleagues following a series of scandals, including over illegal parties in Downing Street during Covid-19 lockdowns.

While the turmoil of the two previous administrations has hamstrung Sunak, political analysts say he has also contributed to his own plight by falling short on promises and failing to connect with voters.

Despite promising to, he has not stopped migrants arriving from France on small boats. National Health Service waiting lists are higher than when he took office. Economic growth is stagnant, although inflation has more than halved.

Sunak has also tried a number of leadership and policy resets that have fallen flat, including watering down carbon net zero commitments in a pitch to motorists and recently talking about extremism.

The rightward tilt comes as the fringe Reform UK party threatens to deprive the Conservatives of key seats, particularly if Farage stands for them as he has teased.

"(Sunak has) been trying to find this magic wand or silver bullet to turn things around but at the moment none of it seems to be moving the dial," Pedley told AFP.

An Ipsos poll published in March found that 58 percent of voters view the Conservatives unfavourably, the highest percentage this parliament. Only 19 percent view them favourably.

The survey gave Sunak a net favourability rating of minus 38, the lowest of any politician included.

- 'Rather awkward' -

Critics often accuse the wealthy ex-financier of being out of touch with average Britons.

"He is a combination of being rather awkward and nerdy, and then if challenged he always sounds really irritable," Ford, politics professor at Manchester University, said.

Sunak is striving to revive his party's fortunes, traversing the country to meet voters as rumours swirl that a disastrous showing in local elections on May 2 could spark a leadership challenge.

He can't seem to catch a break, though.

This week, Johnson slammed Sunak's proposed comprehensive smoking ban as "nuts", while Sunak's spokesperson had to deny that the PM was preparing to run an AI fund in the event of election defeat.

Sunak even offered a "fulsome apology to the Samba community" after photographs of him wearing the Adidas trainers sparked headlines like: "Eight trainers to wear now that Rishi has killed Sambas."

"There's a kind of a doom loop that politicians can get into where they're unpopular," explained Ford.

"The media know they're unpopular so everything they do is reported negatively, which further reinforces their unpopularity."

Political observers say polls usually narrow as voting day nears and suspect liberal Conservatives might ultimately stick with the party to reduce the size of a Labour win and ensure the Tories are an effective opposition.

"Everything at this point really is becoming about damage limitation," said Ford.