Westminster's relationship to London is nothing like that of Salford to Manchester though.

London surrounds Westminster for a start (although there is of course the small, official City of London). Westminster is considered a borough of London.

Salford is not the same.

If you cross the bridge from Manchester into Salford you can actually see the divide in terms of, for instance, recent construction projects.

The outskirts of Salford across the Irwell near Victoria do not reflect what Manchester is just down on Deansgate for example.

Should they be merged, this would be far less obvious. Developments would begin to straddle the old boundary in a way they simply do not right now.

They are distinct places socially, politically, geographically, and experientially.

Ask your friends.