I think you'll find the Canberra became the B-57, not the U-2.
Apart from that, a brilliant invention the Harrier may be, but that doesn't answer the question of why the RAF need it. The only time the Harrier uses its VSTOL capability these days seems to be going on and off a ship, which leads to a whole new argument about whether they should be a Strike asset or a Fleet asset. But if you're just going to be using runways it's a bit over the top.