Caroline Dinenage lashed out after Treasury minister Liz Truss, a prominent Johnson supporter, claimed that scrapping the tax would “help Britain's poorest”.

In a single-word tweet, Ms Dinenage said “Bollocks” – before going on to point out that the tax was already succeeding in persuading firms to cut sugar levels in their drinks.

The comment came after a former public health minister, Steve Brine, vowed to rebel against any attempt to abolish the levy, telling Mr Johnson: “I'll see you in the House of Commons.”

Ms Dinenage added: “To clarify, sugar tax so far has raised 1/3 of predicted tax revenue ‘cos it’s prompted drink co’s to sugar in products, good news.

“To me this isn’t about ‘choice’, tiny kids have no choice over what they’re fed, it’s about incentivising food/drink co’s to use less sugar.”

Her intervention won praise from Sarah Wollaston, the ex-Conservative head of the Commons health committee, now sitting as an independent.

Biggest lies told by Boris Johnson Show all 5 1 /5 Biggest lies told by Boris Johnson Biggest lies told by Boris Johnson Made-up quote for The Times Johnson was sacked from The Times newspaper in the late 1980s after he fabricated a quote from his godfather, the historian Colin Lucas, for a front-page article about the discovery of Edward II’s Rose Palace. “The trouble was that somewhere in my copy I managed to attribute to Colin the view that Edward II and Piers Gaveston would have been cavorting together in the Rose Palace,” he claimed. Alas, Gaveston was executed 13 years before the palace was built. “It was very nasty,” Mr Johnson added, before attempting to downplay it as nothing more than a schoolboy blunder. PA Biggest lies told by Boris Johnson Sacked from cabinet over cheating lie Michael Howard gave Boris Johnson two new jobs after becoming leader of the Conservatives in 2003 – party vice-chairman and shadow arts minister. He was sacked from both positions in November 2004 after assuring Mr Howard that tabloid reports of his affair with Spectator columnist Petronella Wyatt were false and an “inverted pyramid of piffle”. When the story was found to be true, he refused to resign. PA Biggest lies told by Boris Johnson Broken promise to boss In 1999 Johnson was offered editorship of The Spectator by owner Conrad Black on the condition that he would not stand as an MP while in the post. In 2001 he stood - and was elected - MP for Henley, though Black did allow him to continue as editor despite calling "ineffably duplicitous" PA Biggest lies told by Boris Johnson Misrepresenting the people of Liverpool As editor of The Spectator, he was forced to apologise for an article in the magazine which blamed drunken Liverpool fans for the 1989 Hillsborough disaster and suggested that the people of the city were wallowing in their victim status. “Anyone, journalist or politician, should say sorry to the people of Liverpool – as I do – for misrepresenting what happened at Hillsborough,” he said. PA Biggest lies told by Boris Johnson ‘I didn’t say anything about Turkey’ Johnson claimed in January, that he did not mention Turkey during the EU referendum campaign. In fact, he co-signed a letter stating that “the only way to avoid having common borders with Turkey is to vote Leave and take back control”. The Vote Leave campaign also produced a poster reading: “Turkey (population 76 million) is joining the EU”

“Glad to see Caroline, a government health minister, calling out the utter nonsense of the Truss world view,” Ms Wollaston tweeted.

Mr Johnson, the clear favourite in the Tory leadership race, has also infuriated health campaigners after vowing to review “sin taxes” if he becomes prime minister.

He said: “Rather than just taxing people more, we should look at how effective the so-called sin taxes really are, and if they actually change behaviour.”

Critics have also pointed out that, three years ago, as London Mayor, he added 10p on sugary drinks in the cafe at his City Hall HQ and said tackling obesity was “one of the biggest” health challenges.

The threat to the sugar tax – announced by George Osborne in 2016, but only introduced last year – has also thrown the spotlight on lobbyist Mark Fullbrook, now head of daily operations for Mr Johnson's campaign.

When it was unveiled, Mark Textor, who founded the firm CTF with Mr Fullbrook, said: “You can't tax people into healthy submission,” adding that a sugar levy was “the bluntest of policy instruments”.

CTF, which is jointly run by Tory election specialist Lynton Crosby, has given Mr Johnson £23,000 in loans and donations for his leadership bid, it has been reported.

The CT Group, which owns CTF, told the Daily Mirror: “Mark Fullbrook has taken holiday to volunteer for Boris Johnson's leadership campaign and has no contact with any clients.