Jeremy Corbyn said on Friday that there would be "no more hand-holding with Donald Trump" if Labour wins the general election on 8 June.
Speaking at Chatham House in central London, the Labour leader set out his party's approach to defence and foreign policy and said that "waiting to see which way the wind blows in Washington isn’t strong leadership".
While successive Labour and Conservative governments have ended up involved in US-led conflicts in the Middle East, Corbyn suggested that a Labour government with him at the helm would do otherwise.
Talking about the American president, Corbyn said: "Britain deserves better than simply outsourcing our country’s security and prosperity to the whims of the Trump White House."
"While Theresa May seeks to build a coalition of risk and insecurity with Donald Trump, a Labour government will refocus Britain’s influence towards cooperation, peaceful settlements, and social justice," he added.
He also made a reference to the pictures of Trump holding Theresa May's hand in Washington DC earlier this year, concluding that a Labour government would mean "no more hand-holding with Donald Trump".
In his speech, Corbyn – who strongly opposed the 2003 invasion of Iraq – hit out at critics claiming that he would be a weak prime minister and denied that he is a pacifist.
"The best defence for Britain is a government actively engaged in seeking peaceful solutions to the world’s problems," he said. "But I am not a pacifist. I accept that military action, under international law and as a genuine last resort, is in some circumstances necessary."
He also said that if his party were to get a majority next month, his focus would have to be on "strengthening international cooperation and supporting the efforts of the United Nations to resolve conflicts".
"A Labour government will respect international law and oppose lawlessness and unilateralism in international relations," he added. "We believe human rights and social justice should drive our foreign policy."
Though his own position on Trident – he wishes to scrap it – puts him at odds with his party, Corbyn also said he would not seek to overturn last summer's Commons vote to renew the nuclear deterrent system.
"Labour’s support for the renewal of the Trident submarine system does not preclude working for meaningful, multilateral steps to achieve reductions in nuclear arsenals," he added.
The Labour leader then closed his speech with a Martin Luther King quote: “The chain reaction of evil – hate – begetting hate, wars producing more wars – must be broken, or we shall be plunged into the dark days of annihilation."
"We can walk the hard yards to a better way to live together on this planet", he concluded.