Newquay I really don't think you can begin to equate Britain's relationships with its former colonies (later renamed the Commonwealth) and membership of the EU.
Colonisation means invading by force, grabbing lands and taking resources as well as exploiting people (by forcing them to work for you or selling them as slaves). It wasn't an equal relationship at all.
While Britain chose apply for membership of the EU and the members have equal rights.
I need advice for a mutually messy situation
