london british police arrest four men tuesday include serve soldier suspicion belong ban far-right group plan terrorist act men age 22 32 detain suspicion involve commission preparation instigation act terrorism members national action group neo-nazi organization become first far-right group outlaw britain last year murder member parliament jo cox whose kill group praise four arrest make counter-terrorism officer cities birmingham ipswich northampton powys wales arrest pre-planned intelligence-led threat public safety west midlands police say ministry defence mod say number serve members army arrest arrest consequence home office police force-led operation support army mod spokeswoman say subject civilian police investigation would inappropriate comment britain second-highest threat level severe mean attack highly likely suspect islamists kill 35 people year london manchester man die june van drive worshippers near london mosque last month senior police chief say number referrals authorities suspect right-wing extremists double since murder cox kill june last year loner obsess nazis white supremacist ideology uk police arrest four include soldier suspect far-right terrorism