0
You could be referring to counties or boroughs.
England
Scotland
Wales
Ireland (Northern)
The smallest county with multiple districts is Tyne and Wear
Birmingham is in england. It is in the midland and has the second highest populaion of all british districts.
As of 2009, there are 326 boroughs and districts in England. As of 2013, 32 of the boroughs are located in London.