I’ve been going through the literature to double-check Lynn’s Global Bell Curve data. While there is some debate concerning the various magnitudes, the data is robust when it comes to African/White differences, at least, within or between the following countries/regions:
I was unsure of the British data. Based on Lynn’s data there is a .9 SD UK B/W IQ gap .
A parallel, though much smaller gap — about .28 SD  to .5 SD [4, 5] as compared to .7 SD in the US — exists in education . According to Stevens (2007):
“Finally, the largest differences in achievement between various categories of social class or social deprivation can be observed among the highest achieving racial/ethnic groups (White British, Irish, and Indian pupils) and less among Bangladeshi, Pakistani, or Black pupils (Demack et al., 2000; Department for Education and Skills, 2005a). The only exception appears to be the group of Chinese pupils, for which even those from deprived backgrounds outperform almost any other racial/ethnic group, irrespective of their social backgrounds (Department for Education and Skills, 2005a).
(I’ll have to look into the education versus GMA gap some more.)
 Lynn, 2008. The Global Bell Curve. pg. 88
 Evers, te Nijenhuis, van der Flier, 2005. Ethnic Bias and Fairness in Personal Selection: Evidence and Consequences pg. 309. Source: Scott and Anderson, 2003. Ethnic and gender differences in GMA test scores: Findings from the UK
 Bertua et al., 2005. The predictive validity of cognitive ability tests a meta analysis
 Stevens, 2007. Researching Race/Ethnicity and Educational Inequality in English Secondary Schools: A Critical Review of the Research Literature Between 1980 and 2005
 Strand, (in press). The White British-Black Caribbean achievement gap: Tests, tiers and teacher expectations * Use normsinv(%)-normsinv(%) to change % into SD
 Strand, 2010. Do some schools narrow the gap? Differential school effectiveness by ethnicity, gender, poverty and prior achievement. ** I averaged the Black differences