Historically Uk had an agreement with countries like France and Russia before WW-1. It also joined WW-1 as it had interest in economical and land growth
Entente Cordiale
The agreements like Entente Cordiale which was an agreement of peace with France signed in 1904 which made Britain's relation with France more strong. Well the agreement was signed to settle down the situations in Northern Africa as there was a fight between the French and British about the land of North Africa , but after the agreement was signed Morocco was given to France while Egypt was given to the British. France needed help to protect itself from the aggression of Germany , as Germany was growing very powerful due to the quick growth of its producing industrialisation , France needed a country like Britain to help them in that matter. The Britishers had a similar matter as they were also threatened by the Navy Of Germany.