The British drive on the left side of the road, which is the opposite of the practice in most countries. This is a legacy of the British Empire, which once covered a large portion of the world and introduced the practice of left-side driving to many of the countries it ruled.
One reason why the British drive on the left is that it was historically more convenient for them. In the 18th and 19th centuries, when most people traveled on horseback or by carriage, it was safer and more efficient to keep to the left side of the road. This allowed people to keep their right hand free to greet others, to defend themselves, or to control their horses. It also allowed people to pass oncoming traffic on the left, which was the safer and more natural side for horses to pass.
Another reason why the British drive on the left is that it was a way for the British Empire to assert its power and influence. By imposing the practice of left-side driving on the countries it ruled, the British Empire was able to standardize the rules of the road and create a sense of order and control. This helped the British to maintain their dominance over the countries they ruled, and to assert their cultural and political superiority.
Despite these reasons, the practice of left-side driving is not universal in the British Empire. Some countries, such as India and Australia, have switched to right-side driving, either as a result of British influence or as a result of other factors. However, in most countries that were once part of the British Empire, the practice of left-side driving remains the norm.
Overall, the British drive on the left because of historical, cultural, and practical reasons. While this practice may seem strange to people from other parts of the world, it is a deeply ingrained part of British culture and history, and is likely to remain so for the foreseeable future.