Heard a lot of talk buzzing round about people wanting to leave the EU to, "protect our national identity" ...what the hell does that even mean?

If we're talking about protecting our 'national identity', then we're talking about protecting what it means to be British.

But, what does it mean to 'be British' and what part of 'being British' is under-threat by remaining in the European Union?

I'm yet to hear a non-racist, cohesive explanation from anyone on this, yet this banner of 'protecting national identity' keeps cropping up.