Donald Trump has warned Theresa May that a soft Brexit will “kill” the chance of a trade deal with the US, in comments that hugely undermine her attempts to win support for her Chequers deal.

On the first day of the US President’s four-day visit to the UK, he suggested Mrs May was not delivering the Brexit the British people voted for and said she had not listened to his advice on how to negotiate.

“I would have done it much differently,” he said.

Mrs May has spent the week reassuring the public and her own MPs that her controversial Chequers agreement on Brexit will still allow Britain to strike ambitious trade deals with the US and other countries.

But Mr Trump pulled the rug from under her feet by saying: “If they do a deal like that, we would be dealing with the European Union instead of dealing with the UK, so it will probably kill the deal.”