Now then all you experts out there, here's a question for you:
Someone claimed on another forum recently that Liverpool was once in the Kingdom of Strathclyde. I never realised that this kingdom ever stretched that far south!
Liverpool would have been in Rheged in the dark ages. At its height it stretched into southern Scotland and some historians refer to the the peoples living in places like modern day Cumbria as the Strathclyde Welsh. It may therefore be a confusion about this term and the inhabitants of Rheged.
As a 'Kingdom', Strathclyde may have included modern day Cumbria at some point, but that's as far as it goes, at least as far as I understand it.