The reason is that a military defeat of Britain will bring about the disintegration of the British Empire. This would not be of any benefit to Germany.

... instead of trying to grapple with the implications of the story of empire, the British seem to have decided just to ignore it... the most corrosive part of this amnesia is a sense that because the nation is not what it was, it can never be anything again.

I know it is said in missionary meetings that we conquered India to raise the level of the Indians. That is cant. We conquered India as an outlet for the goods of Britain. We conquered India by the sword, and by the sword we shall hold it.

England produced Shakespeare, and the British Empire the six-shilling novel.

I am now a commander of the British Empire.

The fate of the Celt in the British Empire bids fair to resemble that of the Greeks among the Romans.