Boris Johnson and Donald Trump enjoy friendly handshake as world leaders gather for UN summit

Donald Trump made a beeline straight for Boris Johnson as the US President made his maiden appearance at the United Nations, calling for "truly bold reforms" of the organization.

The US President was seen in animated conversation with the Foreign Secretary as the pair met during a gathering at the UN, with the outspoken politicians warmly shaking hands before Mr Trump delivered his debut speech.

The visit of Mr Johnson comes amid a furious row within Theresa May’s Cabinet after he was branded a "backseat driver" for setting out his own vision for a hard Brexit.

His attempted takeover came just days before a major speech in which Mrs May is expected to offer compromise.

Meanwhile, Mr Trump headed to New York amid strained relations with the UK over the bombing at Parsons Green.

Mrs May scolded the US President after he tweeted that the "loser" Tube bomber was already "in the sights of Scotland Yard" – sparking claims he had leaked UK intelligence.

The Prime Minister said: “I never think it's helpful for anybody to speculate on what is an ongoing investigation.”

Mr Trump greeted and shook hands with representatives of 120 countries during the UN gathering, but became engrossed in conversation with Johnson during a warm greeting.

The pair have met before, meeting at Trump Tower just before the business tycoon took office in January.

Speaking at the UN, Mr Trump used his first moments at the world body to urge it to reduce bureaucracy and costs while more clearly defining its mission around the world.

But while Mr Trump chastised the UN - an organisation he sharply criticised during his election campaign over its spiralling costs - he said the United States would "pledge to be partners in your work" in order to make the UN "a more effective force" for peace across the globe.

Mr Trump said: "In recent years, the United Nations has not reached its full potential due to bureaucracy and mismanagement."

In a rebuke over the UN's ballooning budget, he added: "We are not seeing the results in line with this investment."

The US leader pushed the UN to focus "more on people and less on bureaucracy" and to "not be beholden to ways of the past which were not working".

He also suggested that the United States is paying more than its fair share to keep the New York-based world body operational.