Racial homogeneity is a prerequisite to a unified nation. Why would anyone be loyal and loving of a nation that their ancestors had no part in making or experience of? Look at all the past examples of ethnically homogeneous societies that allowed other racial groups into their states.
First it starts off as a cringing minority, then it becomes a fast growing subset of society, with high birthrates, low employment rates and ever plummeting levels of integration. Once the threshold of 20% is reached, we see the inevitable civil wars, partitioning, mass ethnic conflict and the destruction of the nation, or the complete dying out of either the host or the new arrivals, either through mixing or through conquest.
My grandfather fought in the war. Can you imagine he would think it was worth it as he turns on the T.V and sees headlines about tackling white privilege, or how white masculinity is toxic, or how we have to let in refugees with completely alien views to our own?
We were never asked, each decade polling showed the vast majority of British people opposed mass immigration. Now we are on the verge of London, becoming a minority white area. It is no longer Britain if millions of the "citizens" have no cultural, ancestral or spritual connection to the blood and soil of the nation.