The Phantom was developed for the US Navy as a long-range all-weather fighter and first flew in May 1958, before becoming operational in 1961. The US Air Force then realized that the Navy had an aircraft that was far better than any tactical aircraft in their inventory and ordered 543 F-4C variants. There then followed a spate of orders from around the world. In Britain, it was ordered for the Navy and Air Force, but was modified to take the Rolls-Royce Spey turbofan. One of the Royal Navy's Phantoms stole the record for the fastest Atlantic crossing, a record that stood until taken by the remarkable Blackbird. Phantoms have been used in combat in many conflicts throughout its long service history. It was one of America's most utilized aircraft during the long Vietnam War and has been flown in anger in the Middle East by a number of different air forces.