Theresa May condemns Trump's family separation policy and says she will challenge him on UK visit

But prime minister refuses to cancel US president's visit - saying 'we will continue to have a long-standing special relationship'

Theresa May has condemned Donald Trump’s policy of keeping migrant children in cages at the US border and vowed to challenge him when they meet next month.

The prime minister bowed to growing pressure to speak out, condemning the practice as “wrong” – and putting it on the agenda for the US president’s controversial visit to the UK.

“The pictures of children being held in what appear to be cages are deeply disturbing. This is wrong, this is not something that we agree with,” she told MPs.

“This is not the United Kingdom’s approach. Indeed, when I was home secretary, I ended the routine detention of families with children.”

But Ms May refused to cancel the visit, on 13 July, arguing that opposition MPs “consistently” put pressure on her to take the opportunity to confront Mr Trump on issues of concern.

“We do that,” she said. “When we disagree with the United States, we tell them so.

“But we also have key shared interests. It is right that we are able to sit down and discuss those with the president – a president of a country with which we will continue to have a long-standing special relationship.”

The attack came, at prime minister’s questions, 24 hours after Ms May’s spokesman had refused to criticise the policy of separating children from their parents at the US-Mexican border.

The “zero tolerance” approach to illegal border crossings requires adult migrants to be held in custody, pending automatic prosecution – away from their children.

There has been growing worldwide horror over video footage showing the migrant children held in wire cages and sitting on concrete floors.

The “deeply distressing” controversy was raised by Ian Blackford, the SNP’s Westminster leader, who said: “Infants as young as 18 months are being caged like animals.”

Mr Blackford pointed out that a former head of US immigration had admitted that “hundreds of these children [would] never to be reunited with their parents”.

“Orphaned by the United States government. Is the prime minister still intending to roll out the red carpet for President Trump?” he asked.

In reply, Ms May said the caging of the children would be among a “range of issues I will be discussing with President Trump”.

“We are able to have those discussions so that, when we disagree with what they are doing, we say so,” she said, defending the two-day visit.

Former Labour leader Ed Miliband also asked Ms May about the UK’s response – amid surprise that Jeremy Corbyn failed to take the opportunity to do so.

Mr Corbyn instead used all of his six questions to attack the prime minister over her “unfunded” pledge to hike NHS spending by £20bn a year by 2023-24.

Mr Corbyn has previously described the separation policy as “tragic and shocking”, with more than 2,000 children divided from their families in just six weeks on the southern US border.

The US has also provoked anger by announcing that it would withdraw from the UN human rights council.