Donald Trump has warned that he may not have a "very good relationship" with David Cameron after the Prime Minister branded his proposal to ban Muslims from the US as "stupid".

The presidential hopeful also sniped at new London Mayor Sadiq Khan, calling him "ignorant" for comments he made after being elected and warning him: "I will remember those statements."

The presumptive Republican nominee, who is likely to go against Democrat Hillary Clinton in a bid for the White House in November, was speaking to ITV's Good Morning Britain.

Mr Cameron has refused to retract comments he made about the billionaire tycoon's proposed temporary ban on Muslims entering the US, that he branded "divisive, stupid and wrong".