Laura Janner-Klausner, the senior rabbi of Reform Judaism in the UK, told the Observer that the warning signs from history were clea

A British rabbi today delivered a chilling warning that Donald Trump's immigration policies could be a step on the road to genocide.

The intervention by Laura Janner-Klausner comes amid a huge outcry at the treatment of families at the Mexican border.

Donald Trump last week called a halt to the policy of separating children from their parents in detention centres when they try to cross into the US illegally.

But he has robustly defended his hard line on immigration, insisting it was one of the reasons he was elected.

Ms Janner-Klausner, the senior rabbi of Reform Judaism in the UK, told the Observer that the warning signs from history were clear.

'The numbing of empathy, the dehumanisation of other people through the encouragement of disdain are documented stages in history that have led to atrocities and even genocides,' she said.

'What has happened on the US-Mexico border is a moment of reckoning as it points to a systemic toxicity in public discourse and action. This needs to be stopped now.'

She insisted political leaders had a responsibility to speak out now against the decline in respect for other human beings.

Ms Janner-Klausner said Mr Trump's visit to the UK next month should go ahead so that Theresa May can send a clear message to him on the issue.

Donald Trump, pictured disembarking Air Force One in Nevada last night, has faced an outcry over his immigration policy at the Mexican border

Donald Trump last week called a halt to the policy of separating children from their parents in detention centres like this one in Texas

'I believe that our prime minister should be meeting her counterpart, to convey to him in the strongest terms the depth of opposition that these policies have evoked,' she said.

The Bishop of Leeds, Nick Baines, also called for the US president's immigration approach to be challenged.

'The office of the president of the United States has to be respected but in a mature relationship we must speak with him as equals,' he told the newspaper.

'This means that the immorality of his policy requiring the separation of children from their families must be addressed in his conversations here.

'Not to do so would be an abdication of responsibility on the part of our leadership.'