Intelligence sources have warned Putin will seek to take advantage of any difference in UK resolve now that Mr Burnham has replaced Sir Keir Starmer as Prime Minister.
US intelligence agencies believe that Iran's new Supreme Leader, Ayatollah Mojtaba Khamenei, is significantly more open to pursuing a nuclear weapon than his late father.
Saudi Arabia intercepted two ballistic missiles from Yemen, Greek security sources told Reuters, as fighting in a second front in the Iran war escalates.