The Shadow Foreign Secretary claimed Labour would be willing to “work with” Donald Trump while “standing up” to the US leader.
Emily Thornberry has repeatedly criticised Mr Trump for his untraditional approach to the presidency, branding him an “asteroid of awfulness” ahead of a working visit to the UK in July.
Speaking to ITV Peston, the Labour frontbencher insisted her party would change approach if elected into power: “We have always said we would work with Donald Trump but we would stand up to him.
“Holding his hand, holding his hand and holding his hand some more, never standing up to him, that doesn’t work. There is another way of doing it which is to say ‘you are a bully, we’re going to stand up to you, and ‘we’re not letting you push us around.”
Ms Thornberry claimed Britain under Labour would stand together with its allies to convince Mr Trump to give up his isolationist foreign policy and join international efforts to stop the effects of climate change.
She continued: “We’re going to stick with our friends and we’re going to make it clear that on things like climate change, the Iranian nuclear deal, on refugees, on multilateralism, he’s wrong about it.
“We should not be America standing back from the world, you should be working with the whole world and you should be working with us.
“We want to be your friend but frankly, this is not the way to behave.”
Ms Thornberry had to fend off accusations of “endangering” the UK-US special relationship with her “loose talk” against President Trump but she claimed she had made “lots of friends” in Congress to help her maintain close links between the two countries.
But the friendship with her US allies will have to withstand the results of the Midterm Elections 2018 which on Tuesday saw Republicans increase their majority in the Senate.
The Trump administration did manage to hang on to its sphere of influence in the Senate however with some of Mr Trump’s power now stolen out from underneath him, a split in Congress could make the President’s job much more difficult.
President Trump issued a series of tweets declaring the outcome to be a “tremendous success”. The president also took a swipe at the Democrats, threatening them with an investigation at Senate level.
The President later held a press conference in the White House, butting heads with CNN journalist Jim Acosta in an explosive confrontation.
The CNN reporter asked President Trump whether he thought he had “dehumanised migrants” in his Midterm elections campaign rails, challenging the US President to explain why he had referred to the caravan of migrants arriving from Central America as an “invasion”.
A visibly annoyed President Trump responded: “Because I consider it an invasion. You and I have a difference of opinion.
“I want them to come into the country but they have to come in through a process. I want it to be a process and I want people to come in. And we need the people.
“Wait. You know why we need the people? Because we have hundreds of companies moving in.”
The US leader said his party had “stopped the blue wave” – a surge in support for the Democratic Party predicted by some polls earlier in the campaign.
Speaking in the East Room of the White House, Mr Trump said his party had held off Democrats in key Senate races despite a “dramatic fundraising disadvantage” and “very hostile media coverage”.