double first

from WordNet (r) 3.0 (2006)

double first
    n 1: a first-class honours degree in two subjects

from The Collaborative International Dictionary of English v.0.48

Double first \Dou"ble first`\ (Eng. Universities)
      (a) A degree of the first class both in classics and
          mathematics.
      (b) One who gains at examinations the highest honor both
          in the classics and the mathematics. --Beaconsfield.
          [1913 Webster]