London.
London in England
The Barn Owl.
The United Kingdom has the largest population of the two British Isles nations. (UK & Ireland)
Great Britain is the largest island of the British Isles.
Lough Neagh is the largest freshwater lake in the British Isles. Also, it's found in Northern Ireland.
Leeds is the 3rd largest city in Britain today.
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
No. Romania is a long way from the British Isles. It is in easter n Europe and the British Isles are in western Europe.
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.