Right now, it seems that the old British hardcore scene is being overlooked in favor of that of the Americans', and while Crass are hardly straight hardcore, they certainly did create a ruckus that would influence most first-wave hardcore bands. They laid down the beliefs and fury of most all hardcore bands to follow them.
Strange to think that at one time to be a "hardcore" punk meant you probably believed in the furthest left politics possible. Which makes sense, looking at what you'd be listening to. Sure, the DC and Boston scenes fostered some really shitty skinhead scenes, but everywhere else defiance was in there air, if not the music. Bands like The Dead Kennedys and DOA hardly endorsed the system. Black Flag never bothered to write strictly political albums, but they definitely made their thoughts of authority clear with songs like "Police Story", "Spray Paint", and "Damaged" Even the Circle Jerks, a party band, had "Paid Vacation".
Which brings us to Crass. As far as politics "leaning" one way or the other, they were off the map. Their form of music makes other bands of the same era seem structured.
Steve Ignorant, lead vocalist, delivers in a thick cockney accent, going everywhere with his voice from mumbling to John Lennon inspired primal screaming. His lyrics are yet to be matched by any hardcore band, ever. They have a certain foresight, they know that punk is a phase, but they also realize that it can be a valuable tool for self-expression. He sometimes trades off with Joy de Vivre and bassist Pete Wright.
Originally formed after hearing "Anarchy in the UK", Crass naturally have an anti-sell out agenda, though the primary target seems to be the Clash. Thusly starts "White Punks on Dope"; "They said that we were trash, well the name is Crass, not Clash". "System" starts off with a riff mocking "Guns On the Roof".
The guitars and bass play perfectly together, the former providing a sea of static noise for the latter to sift in. The drums utilize a snare, playing ironically militaristic beats to anti-establishment rants.
It's funny hearing people talk about how the Refused revolutionized hardcore with 1999's "the Shape of Punk to Come". Crass had almalgated abbrasive punk with dance, electronica, and radio sampling twenty years before. The difference being, the Refused offered oblique, silly anti-capitalist lyrics that likened themselves more to Rage Against the Machine than Karl Marx, whereas Crass were more than just little kids trying to make a stand.
While definitely not the only proto-hardcore band to exist in the time frame predating the 80's, Crass were definitely the most influential.
Like them or not, they proved how much of a difference one band can make with minimal talent.