Boris Johnson met Mike Pompeo, the US secretary of state, during a day of talks in Washington

President Trump is expected to scrap the nuclear deal with Iran today despite last-ditch attempts by Boris Johnson to persuade him of its merits.

The foreign secretary warned that the West could be forced to take military action against Tehran if Mr Trump tore up the deal. Mr Johnson used an appearance on Fox and Friends, the president’s favourite television show, to urge him not to “throw the baby out with the bathwater”.

He asked: “What if the Iranians do rush for a nuclear weapon? Are we seriously saying we are going to bomb [Iran’s underground nuclear enrichment] facilities at Fordo and Natanz?”

Mr Johnson met Mike Pompeo, the US secretary of state, and Mike Pence, the vice-president, during a day of talks in