Mr Boles, who voted Remain, quit the Conservative Party in April over its stance on Brexit and its failure, in his view, to compromise. He yesterday accused Mr Johnson of being a “compulsive liar” and insisted he will vote Liberal Democrat in the upcoming general election. However, in a June 2016 blog for Conservative Home, Mr Boles asserted that he supported Mr Johnson in the Tory leadership race that ultimately saw Theresa May come out on top.
The MP for Grantham and Stamford expressed his disappointment at the 2016 EU referendum result, but claimed his father would have told him not to be petulant about the result.
He wrote: “I would hear the voice of my late father in my ear: ‘You are in public service.
“‘And the people you serve have made a decision. This isn’t a time to be petulant.
“‘You need to listen to them carefully, and to do what you can to make a success of things.’”
He explained that the reason he backed Mr Johnson is that “the national interest must come first” and that the former Mayor of London is a modern, liberal Tory.
He added that the Prime Minister must be someone who supported leaving the EU.
He wrote: “It would be hugely damaging to an already fragile sense of trust in our political system if the 52 percent of voters and 58 percent of Conservative supporters who backed Brexit were told that this momentous decision would be taken forward by someone who didn’t believe in it.”
Mr Boles added that the country needs someone experienced for this difficult job and someone who can cope with the “relentless pressure and exposure”.
He also argued that the Prime Minister needs to be a “natural unifier” to help bridge the divides that were ramped up during the bitter Brexit campaign.
Finally, he concluded that the Conservatives need a leader who can win elections and “can reach parts of Britain that other Conservatives find hard to reach” – a quality often attributed to Mr Johnson.
Mr Johnson dropped out of the 2016 Tory leadership race, after his ally Michael Gove abandoned his campaign to run himself.
Mrs May, who eventually won the contest, did not fulfill Mr Boles’ criteria – while she was an experienced Cabinet minister, she had come out in favour of Remain before the referendum and so many thought she did not have the conviction to deliver Brexit.
Ultimately, her efforts to secure a Brexit deal failed and she resigned in July.
Mr Johnson was the frontrunner to replace her, but by the 2019 Tory leadership election, Mr Boles' support for him appeared to have completely evaporated.
He said he backed Ruth Davidson, former leader of the Scottish Conservatives, or, given she was not an option, “whoever can come closest to Ruth both in terms of political views but also in terms of personal presence and charisma and authenticity".
Mr Johnson, however, ended up winning by a huge margin and negotiated a new Brexit deal with EU leaders, but failed to get it through the Commons by the October 31 deadline, forcing another delay.
This month, he announced that there will be a general election on December 12 and implored the public to vote Conservative to “get Brexit done”.
Yesterday, Mr Boles launched a ferocious attack on the Prime Minister and the Leader of the Opposition, claiming “you wouldn't trust either of the prime ministerial candidates to mind your children for an hour, let alone run the country”.
Mr Boles, who previously worked for Mr Johnson when he was Mayor of London, accused his former boss of turning the party into a “vehicle for shrill English nationalism”.
However, he also branded Mr Corbyn a “totalitarian” and claimed he is “uninterested in the lives of individual human beings".
Mr Boles added: “[Mr Corbyn] cares only for classes and factions, and the struggle between abstract political forces.”