In the long run, Britain will always tend to ally against the dominant continental power. This is because Britain's enduring interest is to ensure that western Europe doesn't unite under one power, as this would threaten Britain itself. Before German unification, the dominant continental power was usually France.

(I believe this is also why Britain joined the EU in the first place - it's not a threat if Britain has a seat at the table.)

The upshot of this is that Britain was always going to enter WWI once it looked bad for France - if not Belgium, some reason would have been found.

>In the long run, Britain will always tend to ally against the dominant continental power.

Without that, the modern era would probably never have happened. That is because one state would have probably converted Europe into an empire, dominated by a single culture and religion, instead of the great competition of ideas and technologies that happened because there were so many independent states.

One could argue that the Europe of the many states only lead to the horrors and suffering of the world wars, while a multiculturaly diverse but politicaly uniform Europe, built by, say, Napoleon, could have been a United States of Europe. Not being a bunch of countries inflicted so many different nationalisms has worked pretty nicely for them.

I doubt that anything as diffuse as a nation will have a tendency that can be explained in such rational-seeming ways. It's possible that Britain tended towards jealousy towards the dominant continental power, but it is difficult to compare such a theory to reality.

The dominant continental powers have been Rome, France, Germany and Russia. Each have, to put it mildy, their own special characteristics.

* Rome conquered and held on to (most of) Britain.

* France was Britain's neighbour. Each was a potential invader of the other right through the middle ages and most of the modern period.

* Up to 1945, Germany was an extraordinarily belligerent power that made enemies of just about everyone.

* Similarly Britain was a rival of soviet Russia only as part of a broader alliance that went far beyond any attempt at realpolitik.

For all the noise and heat regarding the EU, post cold-war Europe is a remarkably friendly place. By historical standards, there is "against" any more.

And just 20 years later they came close to becoming a single country:

https://en.wikipedia.org/wiki/Franco-British_Union#World_War...