The Foreign Secretary went on the attack on Thursday morning with a scathing column in The Sun followed by a string of media appearances to make the case for the Tories in the upcoming General Election.
In his article he described the Labour leader as a “benign herbivore” and a “mutton-headed mugwump” capable only of “meandering and nonsensical” speeches, prompting widespread bemusement and reaching for dictionaries.
But in interviews on the BBC, Good Morning Britain and Radio 4, his attacks on Corbyn were drowned out as he was grilled on why the public should trust what he says after the now-infamous £350 million NHS pledge made on the side of a bus during the EU referendum campaign.
First up was Good Morning Britain.
Johnson also squirmed over Theresa May’s flagship pledge to cut net migration to “tens of thousands”, or less than 100,000 a year.
“It depends how many tens you are talking about.. I don’t want to get into numbers.”
Asked about May’s insistence on including students in her migration target, Johnson again ducked the issue, preferring to say students have “enormous practical economic value” and “I value international students”.
And he ducked detailed questions about Britain’s looming Brexit “divorce” bill, saying only that “money before substantive talks - that is obviously not going to happen”. But he didn’t define whether those talks were on trade or withdrawing from the EU.
Shadow foreign secretary Emily Thornberry today hit back for Labour, saying: “It seems Boris Johnson has finally been allowed out of hiding, on the condition he only talks delusional nonsense.
“He talks about creating a ‘global Britain’, yet the Tories have overseen the greatest diminution of British influence on the world stage in a generation.
“With his crass and offensive remarks Boris Johnson has single-handedly damaged Britain’s chances of getting a good deal with the EU.
“And after his broken promise of £350m a week for the NHS, why should anyone believe a word he says?”