The veteran MEP noted that Theresa May still has a couple of weeks left before her premiership is expected to terminate, and that she could "as a parting gift, still appoint a new ambassador who might be perfectly bad like Sir Kim Darroch", but that if the decision does fall to Mr Johnson, and Mr Johnson does make the offer, he might not be able to accept it.
"One could always look back and say, "If I'd sat down and talked to people more often", she said, in reference to any regrets.
"There is a real difference". The runoff vote will be announced July 23.
May, who is now serving as caretaker Prime Minister during the course of a leadership contest between United Kingdom foreign secretary Jeremy Hunt and former foreign secretary Boris Johnson, was forced to announce her resignation amid mounting rebellion within her own Cabinet over Brexit at the end of May.
"As we know, it isn't as straight forward as we would like it to be because the Prime Minister has tried on several occasions to do that", she added.
"I had assumed mistakenly that the tough bit of the negotiation was with the European Union, that Parliament would accept the vote of the British people and just want to get it done, that people who'd spent their lives campaigning for Brexit would vote to get us out on March 29 and May 27", she told the Mail. "A decision was taken just get on with it and they are not in that same polarised way that Parliament has been about this issue", she said.
"If a male Prime Minister's voice had broken up, it would have been said "what great patriotism, they really love their country".
"Boris is, I believe the necessary choice for our Prime Minister at this crucial time and moment in history", she said.
Britain's Conservative Party leadership candidate Boris Johnson during a visit to the port of Dover, southeast England, while on the campaign trail, Thursday July 11, 2019.
The cabinet minister said she was backing Jeremy Hunt in the leadership race, who has previously said a no-deal Brexit would be a "last resort".