Stocks plummeted on Wednesday as tensions flared in the Middle East with the US threatening further attacks on Iran.The FTSE 100 closed down 176.84 points, 1.7%, at 10,489.04, and the FTSE 250 ended down 361.18 points, 1.5%, at 23,017.64, while the AIM All-Share fell 11.11 points, 1.4%, to 758.07.Oil prices jumped and stocks slumped after US President Donald Trump said the ceasefire with Iran was “over” as fighting flared, sparked by Iranian attacks on ships in the vital Strait of Hormuz.Tehran insists on controlling the key shipping route, saying it will charge fees for passage and threatening to hit vessels that deviate from its authorised route.Iran’s military has struck at least three ships in recent days, prompting extensive US strikes against Iranian targets followed by retaliatory a