Race issues bleg

After reading Renee's article "Light skin vs dark skin", about the discrimination and prejudice that divides North American black folks based on the perceived lightness or darkness of their skin, I am left puzzled. Renee's article makes it clear that she believes that the divide in the USA especially is influenced heavily by nuances of the slavery era and its aftermath (e.g. "A simple glance through the photographs of the first Black sororities will reveal that the first Blacks to attain an education were overwhelmingly light skinned.") I cannot talk to how justified that is, and I take Renee's word for it that this is the history of the divide in the USA. But that leads me to my bleg:

I am vaguely aware that something similar exists in the UK. Obviously, although Britain did have African slaves for a long time, their history was not the same as African slaves in the USA, so it seems unlikely that the historical causes are the same.

A simple google search limited to UK sites only with search terms [light skin vs dark skin] leads me to some interesting links but nothing that explains where this comes from in UKian black society. One link led me to a discussion thread on a board for Nigerian-Britons (to use a term analogous to "African-Americans"), asking why Nigerian-Britons had a tendency to distance themselves from being described as "Black" or "African", and emphasising a tendency to prefer lighter skin tones. This gives me the possibility that it's related to the history (that I've learned from watching Open University programmes on televison) that the Nigerian immigrants saw themselves as superior to the "slave-stock" Afro-Caribbean immigrants of the previous (Windrush) immigration wave. But this is just a guess.

So, although it's nobody's job to teach me, maybe someone out there can give me some clues so I can go out and find out this stuff for myself?