Must have been bored today.
Started looking at en.wikipedia.org/wiki/Demographics_of_Europe then got to....
Different ways of counting city population....:
Largest_urban_areas_of_the_European_Union: Manchester is 7th largest area with 3.8 mill people.
Largest_European_metropolitan_areas: Manchester is 11th with 4.2 mill people. However in the Manchester City itself is only 440,000 (but that does not include Salford, Oldham, Trafford, Sale, etc).
Larger_Urban_Zones_(LUZ)_in_the_European_Union: Manchester is 14th with 2.8 mill people. The scousers keep interfering in the others, but this is perhaps the proper size of Manchester.
Ps. Looking at it differently
www.top500.de/cities/ranks/page000.php: Oslo is Europe's fifth largest city!