The British Empire would absolutely not allow a unified European continent!
For a considerable period, Britain enjoyed keeping the European continent in turmoil. Situated in the northwest corner of the British Isles, separated from the European continent by the English Channel, the other end of which was the famous land of culture and romance—France. Yet, the shallow ten-thousand-channel couldn't entirely isolate Britain from France. In history, these two nations forged deep-seated enmity. During the Hundred Years' War, Britain almost annihilated France. However, after the emergence of Joan of Arc, the tide of the war turned shortly thereafter. Eventually, France not only reclaimed all its territory but also occupied all of Britain's "legitimate territories" on French soil. Through the Hundred Years' War, the French nation formed a strong sense of national cohesion and became the earliest country to establish unity on the European continent.
The defeated party, England, reduced its connections with the European continent after the Hundred Years' War. It gradually embarked on a different development path from the European continent, politically, economically, and culturally. Of course, this doesn't mean that the European continent had no influence on Britain, or that Britain had no interaction with the European continent. In reality, during the reign of William III, Britain and France once again entered into a competitive relationship.
The relatively isolated geographic environment, the cultural differences compared to the European continent, determined that Britain would not form a stable alliance with any country on the European continent. At the same time, Britain's continuous economic development since the sixteenth century, with the prevalence of mercantilism principles, demanded the extensive expansion of foreign markets and the restriction of foreign goods entering Britain (i.e., trade protection). Therefore, Britain did not wish for a powerful economic rival on the European continent that would compete with it in overseas trade. Additionally, maintaining the division of the European continent created difficulties for some countries (such as Germany) to form a unified market internally. This way, British goods could easily enter various states. Based on this, Britain, on the one hand, hoped for relative stability on the European continent to facilitate the circulation of its goods in European markets. On the other hand, Britain did not want a powerful continental country to emerge, posing strong competition in terms of economy and overseas colonies.
Until the rise of Napoleon, Britain's interference in the European continent was not substantial. However, Napoleon changed this practice. During Napoleon's rule, France was undoubtedly militarily robust, conquering far and wide, nearly placing the entire Western European continent under the control of the First French Empire. This emperor was not satisfied; he wanted to conquer the entire Europe, including the distant England. Consequently, he sent naval forces several times to attack the British mainland. Although these attempts ended in failure, they made Britain fully aware that if a hegemon appeared on the European continent, it would pose a significant threat to Britain's security—even though Britain had considered this before, it was not a crucial factor because, historically, no country could threaten the British mainland.
Therefore, at the Congress of Vienna convened after Napoleon's downfall, Britain vigorously sought to contain France. On the other hand, to avoid the emergence of another "France", in the Saxon question, Britain sided with France, strongly opposing Prussia's occupation of the Kingdom of Saxony—such an outcome would greatly strengthen Prussia. Since then, Britain has actively pursued a balance of power strategy on the European continent. Whoever had more influence, Britain stood against them to maintain the balance of power on the European continent and safeguard Britain's territorial security and economic interests. This laid the foundation for Britain's implementation of splendid isolation in the 1860s and also gave rise to Palmerston's classic quote:
"A country does not have permanent friends, only permanent interests."
Although in World War I, Britain formed alliances with France and Russia, at the Versailles Conference after the war, Britain continued to pursue a policy of balance. It opposed the dismemberment of defeated Germany and the massive reparations demanded by France, aiming to retain German strength to prevent France from dominating Europe again.
In Churchill's "The Second World War Memoirs" in later years, he wrote, "Britain's foreign policy for the past 400 years has been against the emergence of the largest, most aggressive and domineering country on the continent." He further stated, "Britain always joins the weaker side, unites with them, and defeats and frustrates the military hegemon on the continent, whoever he may be and whichever country he rules." In essence, Churchill's words suggest that Britain follows a diplomatic policy of maintaining "continental balance".
Why does Britain not want to see European unity?
There are several reasons for this.
Britain is located on the northwest border of the European continent, separated from it by the English Channel, making it somewhat isolated overseas. If Europe were to unify, the capital, economic, and cultural centers would not be located in Britain. Britain might face marginalization, severely damaging its interests. If Britain allows European continental countries to unify, then Britain might also be subject to unification next. Therefore, Britain seeks ways to undermine the unity of Europe and the European continent.
Moreover, for centuries, Britain has been the world's foremost colonial empire, with its economic interests primarily derived from vast overseas colonies rather than the European continent. The economic development level of Britain's mainland is higher than that of most areas in Europe. Britain does not want to distribute its established interests equally among its less affluent brethren. Brexit in later years is also based on this reason.
In addition, there are religious, cultural, and other factors. In the eyes of the British, a Europe in a divided state best serves the interests of the British Empire. Naturally, there is no intention to pursue unity.
After the meeting, Churchill immediately sent a confidential telegram to the overall commander of the British Expeditionary Force, Lord Gort. The essence was to ensure the safety of the expeditionary force, and if the situation changed, he could decide to evacuate independently.
Everyone knows that the alliance between England and France was for political purposes only. Britain does not want to see a unified Europe, as it would consolidate its position as a world hegemon. However, it never thought about standing by France's side through thick and thin. Although abandoning allies to save oneself might bring unfavorable consequences, Churchill could no longer be concerned about the aftermath.
To evacuate the expeditionary force, even if it means betraying its ally, is an acceptable sacrifice. After all, the guiding principle of the British Empire is "there are no permanent friends, only permanent interests".