THERESA May has joined other leading politicians in criticising Donald Trump for not singling out white supremacists and neo-Nazis for criticism following deadly unrest in Virginia, insisting there was "no equivalence" between fascists and their opponents.

Pressure is now building on the Prime Minister to stop the planned state visit by the US President, already postponed from this year due to the level of expected protests on Britain’s streets.

Mrs May, back from her three-week summer holiday, spoke out after Mr Trump failed to condemn far-right demonstrators outright for violence in Charlottesville in which a woman was killed.

READ MORE: Border diplomacy: Ireland's Varadkar and UK's May hope to maintain soft border post Brexit

He claimed there was “blame on all sides," apparently equating the actions of far-right demonstrators with those protesting against them.

But Mrs May said: "I see no equivalence between those who propound fascist views and those who oppose them. I think it is important for all those in positions of responsibility to condemn far-right views wherever we hear them."

Asked about Mr Trump's comments in the wake of the violence, the PM told reporters in Portsmouth, where she was attending the welcome for the £3 billion aircraft carrier Queen Elizabeth to its home port: "As I made clear at the weekend following the horrendous scenes that we saw in Charlottesville, I absolutely abhor the racism, the hatred and the violence that we have seen portrayed by these groups.

"The United Kingdom has taken action to ban far-right groups here, we have proscribed certain far- right groups here in the United Kingdom. And there is no equivalence."

READ MORE: Border diplomacy: Ireland's Varadkar and UK's May hope to maintain soft border post Brexit

Mrs May spoke out after opposition politicians called for the state visit, now expected some time in 2018, to be postponed.

Sir Vince Cable, the Liberal Democrat leader, said: "Donald Trump has shown he is unable to detach himself from the extreme-right and racial supremacists.

"The fact he remains highly dependent on White House advisers from the extreme-right shows he is firmly anchored in this detestable world view.”

He added: "It would be completely wrong to have this man visit the UK on a state visit."

Nia Griffith, the Shadow Defence Secretary, tweeted: "A state visit by #DonaldTrump would shame this country and betray all we stand for. Theresa May should revoke the invitation immediately."

READ MORE: Border diplomacy: Ireland's Varadkar and UK's May hope to maintain soft border post Brexit

Jeremy Corbyn has already called for the cancellation of Mr Trump’s state visit. Earlier this week following the violence in Charlottesville, the Labour leader said: “What happened in Charlottesville was the KKK [Ku Klux Klan] and its supporters, white supremacists, arrived in Charlottesville in order to cause trouble. Surely every president of every country in the world...should be able to condemn that."

Ruth Davidson, the Scottish Conservatives leader, tweeted: "The President of the United States has just turned his face to the world to defend Nazis, fascists and racists. For shame."

Communities Secretary Sajid Javid posted: "Neo-Nazis: bad, Anti-Nazis: good, I learned that as a child. It was pretty obvious."

Commenting on how David Duke, the former KKK leader welcomed Mr Trump’s remarks, Nicola Sturgeon said: “When the likes of David Duke praise you, you are on the wrong side. There are no ‘fine’ Nazis. We must all stand firm against the far-right.”

READ MORE: Border diplomacy: Ireland's Varadkar and UK's May hope to maintain soft border post Brexit

The First Minister added: “Some issues are just too fundamental for diplomatic silence. This is one of them.”

Violence erupted in Charlottesville on Saturday after a group of far-right extremists gathered to protest against a decision to remove a statue of a Confederate general.

Heather Heyer, 32, later died when a car was driven into crowds as anti-fascist demonstrators clashed with the white supremacists.

Mr Trump faced heavy criticism in the immediate wake of the unrest after he said there was blame on "many sides".

He took two days to condemn the actions of the far-right groups in particular, eventually branding the KKK, neo-Nazis and white supremacists "repugnant to everything that we hold dear as Americans", in a statement on Monday.

However, during a turbulent press conference at his Manhattan residence on Tuesday, the President appeared to have reverted to his previous position.

READ MORE: Border diplomacy: Ireland's Varadkar and UK's May hope to maintain soft border post Brexit

He acknowledged there were "some very bad people" among the statue protesters, but added: "You also had people that were very fine people, on both sides."

In the hours after the comments the hashtag #ImpeachTrump trended worldwide on Twitter.

Meanwhile, dozens of celebrities have hit out at Mr Trump’s remarks, including film star Ben Stiller, author JK Rowling, US basketball star LeBron James and model Chrissy Teigen.

On Twitter, Mr Stiller called the controversial press conference the "worst message I have ever heard a president put out to the world".

Ms Rowling noted: “One good thing about that abomination of a speech: it's now impossible for any Trump supporter to pretend they don't know what he is.”

Mr James said the US President had made hate "fashionable again" while Ms Teigen said: “He is actually racist and means this…what a f***** idiot."

Elsewhere, a post by Barack Obama responding to the white nationalist rally in Charlottesville has become the most-liked tweet in history with 1.2 million retweets.

In a series of posts, the former President said: "No one is born hating another person because of the colour of his skin or his background or his religion.

"People must learn to hate and if they can learn to hate, they can be taught to love, for love comes more naturally to the human heart than its opposite."