Forgive my naivety here - when you say "Britain first", is this an organisation, or are you having a go at people who put Britain first ?
If "Britain first" is like the BNP, then fair enough, deride it, but if it's just an attitude that you should do what needs to be done to look after your country and your way of life, then what's wrong with that ?
Britain First was one of the several splinter groups formed by ex-BNP activists when the BNP went tits-up. It's every bit as unpleasant and racist as the BNP was, as you'd expect given it's all ex-BNP. Like our very own Ironside that you're such a fan of. It mainly specialises in clickbait memes on Facebook (usually along the lines of "We like poppies") so it can trick people into sharing and liking, and so pretend it's got more support than it really has, mosque invasions and sending a couple of van loads of dickheads into Asian areas to drink lager and smoke in front of people who look like they might be Muslim in the name of "Christian patrols". Oh, and they recently gravely upset Lee Rigby's family by continuing to use his image in their nasty racist propaganda despite repeated requests from the family for them not to do so.
So yes, it's very much like the BNP, and the BNP before it smartened itself up to pretend to be electorally acceptable.