Green Cross Code Man
Wunt be druv
Haha, I was meaning BNP as an example more in the sense of Nationalistic racists rather than nationalistic in the way I consider I am.Quite right too. The BNP may be many things, but being a British nationalist party leads to hazard a guess they're probably not too keen on breaking up the union.
A Google search reveals there was actually a petition from 2016 after the Brexit vote calling for English independence, but it only got about 2500 signatures.
There does appear to be a political party dedicated to the cause already in existence - https://www.englishdemocrats.party/about
English nationalism is small time, but everything big tends to start as something small.