UK PM Starmer warned his cabinet about potential US strikes on Iran.  
Just a day earlier, he claimed Trump hadn’t signaled involvement.  
Officials called the situation "serious and volatile."  
Discussions included whether Trump might use a UK-US base for attacks.  
Britain aims to stay out of Israel-Iran conflicts.  
They fear actions risking their Tehran embassy, a key Western post.  
Starmer raised the issue at a Whitehall emergency meeting.  
Attendees included top ministers, military chie