Australia are bracing for more harsh treatment from crowds at Headingley this week, after their dramatic 43-run win at Lord's gave them a 2-0 lead in the Ashes series.
England media on Monday laid the boot into Australia with several references to the word "cheat" on front and back pages, with images from within the Lord's long room.
Both the Daily Express and Metro ran with the bodyline-themed "Just Not Cricket" headline, while London's Daily Telegraph labelled it an "underhand dismissal".
It comes after both England captain Ben Stokes and coach Brendon McCullum hit out at Australia in the dramatic postscript to Sunday's dramatic finish, saying they would have withdrawn the appeal.
Sunak has now backed the pair's claims, with a spokesperson for his office telling reporters in the UK that he was unhappy with Australia stumping Bairstow after he ducked a ball and wandered out of his crease.Â
"The prime minister agrees with Ben Stokes. He said he simply wouldn't want to win a game in the manner Australia did," a spokesman for Sunak's office said.
"The game did provide an opportunity to see Ben Stokes at his best and it was an incredible Test match and he has confidence England will bounce back at Headingley."
When asked whether Sunak believed Australia's had not upheld the spirit of cricket, his spokesperson said: "Yes."
Australia have defended the stumping, adamant Bairstow himself has thrown the ball back at the wickets while wicketkeeping in the same Test.
They also believe a decision on whether the ball was dead at the end of the over is one for the umpires, a point Stokes has largely disagreed with.
Sunak's views are at odds with several former players, with former England red and white-ball captains Andrew Strauss and Eoin Morgan among those defending Australia.
"There was absolutely nothing wrong with it but, of course, the crowd will see it through English patriotic eyes," Strauss said on Sky Sports.
"Bairstow was being dozy going outside of his crease. I was pretty comfortable with what Australia did."
India star Ravichandran Ashwin has also backed Australia's actions, having himself been involved in mankad controversies.
"The keeper would never have a dip at the stumps from that far out in a Test match unless he or his team have noticed a pattern of the batter leaving his crease after leaving a ball like Bairstow did," Ashwin posted on social media.
"We must applaud the game smarts of the individual rather than skewing it towards unfair play or spirit of the game."