The Barn Owl.
London.
London in England
The United Kingdom has the largest population of the two British Isles nations. (UK & Ireland)
Ben Nevis in Scotland at 1,344 metres or 4,409 feet. Ben Nevis is the highest mountain range in the British Isles.
Great Britain is the largest island of the British Isles.
South west
Lough Neagh is the largest freshwater lake in the British Isles. Also, it's found in Northern Ireland.
The third largest city in the British Isles is Manchester, which is located in England. It is a major city known for its industrial heritage, cultural attractions, and vibrant music scene.
The Angles and Saxons were the largest Germanic tribes that invaded the British Isles. They are generally called (together with the Jutes) the Anglo-Saxons.
No, there is no single leader of the British Isles. What is called the British Isles has a number of countries and they each have their own leaders. The British Isles is a geographical reference, not a political one.
British Isles
Geographically, The British Isles are the main islands of Britain and Ireland and all of their off-shore islands. The longest river in the British Isles is therefore the River Shannon in Ireland and the second longest is the River Severn in Britain - which is fractionally longer than the River Thames.