CBS News contributor Simon Bates is a veteran British radio and television presenter, and commentator on British politics, culture and society.

London -- Britain's government is going through a painful rebirth. If the polls and predictions are correct, next week former London Mayor Boris Johnson will become the new Prime Minister of the United Kingdom. He's promised to make an early trip to Washington to bond with President Donald Trump and to sow the seeds for a new trade deal between the two countries.

Johnson has also pledged to take Britain out of the European Union -- come what may -- by the end of October, even if his government hasn't arranged a withdrawal deal with the EU by then. That could lead to chaos at Britain's borders, with lines at the ports and shortages of medicines and agricultural products.

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If it comes to that, Britain might very well need the U.S. to help out; the U.K. could need a sort of mini re-run of the Marshall Plan, America's $12 billion program of aid to an impoverished Western Europe after the end of World War II. While the U.K. is unlikely to seek any direct financial aid, it will be looking to hammer out a favorable trade deal with its closest ally.

But in the era of President Trump, many Britons are questioning whether the United Kingdom can really rely on the current U.S. leader in a time of national crisis. Although our countries are meant to be the closest of allies, last week President Trump insulted Britain's Ambassador in Washington in such personal and undiplomatic terms that he was forced to resign.

The wacky Ambassador that the U.K. foisted upon the United States is not someone we are thrilled with, a very stupid guy. He should speak to his country, and Prime Minister May, about their failed Brexit negotiation, and not be upset with my criticism of how badly it was... — Donald J. Trump (@realDonaldTrump) July 9, 2019

Ambassador Kim Darroch's crime was to report back to London -- in a highly confidential diplomatic cable that was leaked to a British newspaper -- on the Trump administration, as he saw it. He described the White House as dysfunctional, clumsy, faction-ridden and inept., and Mr. Trump turned on him.

To many in the U.K., it seems a little strange that we should be about to turn our backs on our closest European neighbors, and throw all our eggs into one basket -- a basket held by President Donald Trump.

Then there was Mr. Trump's fight this week with the four Congresswomen of color -- "The Squad."

The things that he said about them reverberated across the Atlantic, and both Boris Johnson and outgoing British Prime Minister Theresa May criticized Mr. Trump's language.

Surely Johnson must be thinking, as he prepares for power: if President Trump behaves that way toward his own countrymen, what's he going to do to us?

CBS News producer Martin Levene contributed to this report.