We calculated the Dirac-point energy and Fermi velocity from E − k slices (some of which are shown in Fig. 1) near the graphene K point, by analysing the band dispersions. We extracted momentum-distribution curves (MDCs; that is, intensity as a function of momentum I(k) at constant energy), and found the positions of the branches on each side of the Dirac cone by fitting Gaussian peaks. After repeating this process for each MDC within |E − E F | < 1 eV, we fit a straight line of the same absolute slope to each side, yielding the Dirac point, E D , from where the lines cross and the Fermi velocity, v F , from their slope. In cases in which one side was much more intense than the other, we used only the more intense side to find v F . The extracted velocity is here plotted against gate voltage. Evidence has previously been reported36 of a reduction in v F of up to 20% near E D in graphene films at low doping levels (roughly 1 × 1012 cm−2). This corresponds to a subtle distortion of the bands at E D , which the spectrometer at Elettra does not as yet have the resolution to probe, and could not be detected by the above procedure which assumes purely linear dispersion. Note that the variations seen in this figure can be explained by systematic errors, taking into account experimental limitations such as the very weak emission from one branch and the sensitivity to the exact alignment of the momentum slice with the Dirac point.