LONDON, June 4 (Xinhua) -- Visiting U.S. President Donald Trump has been criticized by senior politicians and political commentators for his "distasteful interference" in British politics after claiming Boris Johnson would make an "excellent prime minister."
His apparent endorsement of the former British foreign secretary came during an already controversial state visit with the Conservative Party leadership race hanging in the balance.
Politicians from all of the main British parties have warned Trump against breaking the longstanding convention of neutrality.
Former British Foreign Secretary Malcolm Rifkind has told media that the president's "narcissistic and egocentric" comments are "unprecedented" and slammed them as "distasteful interference in other people's business."
The British Opposition Labor Party leader Jeremy Corbyn and leader of the Liberal Democrats Vince Cable have also condemned the remarks.
Corbyn said: "President Trump's attempt to decide who will be Britain's next prime minister is an entirely unacceptable interference in our country's democracy."
Trump's comments came as 12 Conservative MPs are vying for the top job left vacant by the outgoing British Prime Minister Theresa May who has pledged to step down as Conservative leader on June 7.
In a press conference on Tuesday in London, Trump said he believes that Boris Johnson would do "a very good job" as leader of the governing Conservatives.
Professor Anthony Glees, an expert on European politics from the University of Buckingham, described Trumps' interference in internal British politics as "odious".
Referring to the system in Britain where the prime minister is not chosen by the country, but emerges from a vote among members of the governing party to choose their leader, Glees told Xinhua: "That the choice of leader should first be influenced openly by a U.S. president pushing Boris Johnson is just horrifying."
British media said Trump is expected to meet several of the leadership candidates, including Secretary of State for Environment, Food and Rural Affairs Michael Gove, during his three-day visit.
This is not the first time that Trump has been criticized for siding with British politicians in an inappropriate manner. In 2016, he suggested that the then leader of the Ukip Nigel Farage should become the UK's ambassador to the U.S., prompting a spate of accusations. It is unprecedented for an incoming U.S. president to ask a world leader to appoint an opposing party leader as ambassador.
Political expert, Professor Iain Begg from the London School of Economics, told Xinhua Tuesday that while Trump's comments may be good for headline writers, the impact on British politics will probably be ephemeral.
"Farage, probably, will welcome his endorsement, but I wonder whether Boris Johnson might be less enamored of it," said Begg.
Feelings in Britain are mixed, with some saying Trump's thumbs up for Johnson could harm his chances of winning the top job in British politics.
Former British cabinet minister Andrew Mitchell has doubted that whether Trump's "unusual" words could move many votes in Westminster.
"It is certainly unprecedented and could indeed backfire," he said.