The British Empire did not exist as an entity, it was just a propaganda phrase, hence the modern confusion that "empire" means a bunch of colonies rather than a state ruled by an emperor.
The confusion probably arose because the British monarchs from Victoria on did have the title of Emperor (sometimes they were called King-Emperor or Queen-Empress), but only Emperor of the Empire of India, essentially filling the old Mughal Emperor's shoes.
Incidentally, back in 1803 or whenever it was when Napoleon declared himself Emperor and the Austrian Archduke did likewise, the Austrian (whose name I don't recall) urged his Prussian and British counterparts to do the same to devalue Napoleon's declaration. Both declined, and King George III specifically turned down "Emperor of the Britons" because he thought it was a silly made-up title and didn't want to bring himself down to Napoleon's level of vulgarity.