This is your opinion, and it is an unpopular one at that. The British Empire is a term widely used by historians to describe the colonial empire that existed formally up to the handing over of Hong Kong in 1997. The same is, of course, true with the French empire as well.Not every nation can just be declared as an empire like that.
The British empire ceased to exist during the 19th century.
It was just a colonial power during WWII.
The Ottoman empire had collapsed after WWI, and the only thing that was close to an empire during WWII was the USSR, but it didn't collapse right after WWII.