But she said the United Kingdom had a "long and enduring special relationship" with the U.S. and Mr Trump's visit next month was an opportunity to raise a range of issues.
Theresa May has said Donald Trump's approach to child migrants in the United States is "wrong" and "not something we agree with". It will be Trump's first visit to Britain since being elected president in 2016.
"Yes, I mean he has to see the head of state". Facing domestic and worldwide outrage, Trump issued an executive order Wednesday that ends family separation, instead keeping families together in federal custody while awaiting prosecution for illegal border crossings.
Mr Trump's tough new immigration policy has seen more than 2,000 children separated from the parents and placed in holding centres as the adults are prosecuted for entering the U.S. illegally.
Later, asked if he was happy for the President's July 13 visit to Britain to go ahead, the Highland MP replied: "On the basis of where we are now, it is right the Trump visit is called off".
But condemnation of the policy has been widespread; from world leaders and captains of industry to ordinary members of the public.
Trump has yet to visit Britain in any capacity since his election.
But she has now branded the policy "deeply disturbing" after she faced a direct grilling at Prime Minister's Questions. -British relations on numerous occasions.
PM May first invited the USA leader for a state visit following her trip to the White House in January 2017.
Prime Minister Theresa May invited Trump for a state visit when she met him in the United States shortly after his inauguration in January 2017.
Britain's longest-serving monarch, who is now 92 years old, has met with nearly all serving US presidents during her reign. It is rumored that the meeting with Trump will take place at Windsor Castle, where Prince Harry married Meghan Markle during a lavish ceremony in May.
But his arrival is also expected to draw mass protests, with campaigners poised to demonstrate against Mr Trump's divisive policies.
Downing Street, Buckingham Palace and the U.S. embassy have all been approached for a comment.