This issue is a variant of Marvel Tales (Marvel, 1966 series) #132 [Direct]. There exist further variants.
Cover is a reprint of AMAZING SPIDER-MAN #155 but with a few color changes and original text is changed to accomodate the Captain Britain reprint.
Second chapter in a 3 chapter reprint rearrangement of Captain Britain #1-2.
Original titles were, "The Origin of Captain Britain" & "From the Holocaust, A Hero".