The U.S. Air Force’s heaviest bombers are expected to arrive at British bases within hours, suggesting that Donald Trump‘s mega-attack on Iran that he has dubbed the ‘big one’ is imminent.

America’s stealth air fleet including its B-1s, B-2s, and B-52s are said to be on their way to Diego Garcia in the Chagos Islands and RAF Fairford in Gloucestershire.

The strategic bombers, costing up to $2billion each, can carry out long-range missions without detection while carrying the world’s most devastating missiles.

Read more: U.S. stealth bombers land at UK bases for ‘the big one’ after Trump hints he could drop the ‘mother of all bombs’