No, it’s not Karma.
Also, this “miscegenation” will not reduce racism or change the racial and power hierarchy of England, or the rest of the world. Just look at Latin America, where the White invaders engaged in open and widespread race mixing with the Natives, and African captives. Today they have hundreds of racial classifications for the wide array of color tones, hair textures, and racial mixes; but without exception, the Whites and the lighter racial mixes are on top of the economic and power heap, and the Africans and darker mixes are on the bottom.
You can’t fuck, assimilate, or integrate your way to liberation, not even if you are in a racial majority, just look at South Africa. Hell just look at the Globe, Whites are the planetary minority, but they dominate the global economies.
Also, these mixers are often devoid of any racial consciousness, or revolutionary ideology, so they are no threat White Domination, no matter how many White women they impregnate, they will simply produces more Human Resources for this system to exploit and consume.
Our only solution is Revolutionary Pan-Africanism, targeted at fully dismantling the Systems and Institutions of White Domination.