President Trump, who has been a fierce critic of the Prime Minister over the UK's reluctance to help the US in the war with Iran, has now taken another swipe at him. Speaking outside the White House before beginning his journey to China for a highly anticipated state visit with counterpart Xi Jinping, Mr Trump was asked if he had any advice for the under-pressure Prime Minister.

He replied: "Well, my advice has always been open up. Open up your oil in the North Sea.

"You've got one of the great oil finds anywhere in the world and you’re not using it and you're not allowed to use it and it's one of the best in the world.

"Open up your oil in the North Sea and get tough on immigration. Europe is being very very hurt by immigration."

Asked if Sir Keir should resign, Mr Trump responded: "That's up to him."

The US President then continued his outburst about what he suggested was untapped energy from North Sea oil fields, adding: "You're getting killed on windmilling your country to death."

As he departed for his trip to China he also told reporters at the White House that he will have a "long talk" with Xi Jinping about Iran war but adds "we have Iran very much under control" so he will not need the Chinese Presidents help.

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