  We extend the phase diagram of SU(N) gauge-fermion theories as function of
number of flavours and colours to the region in which asymptotic freedom is
lost. We argue, using large $N_f$ results, for the existence of an ultraviolet
interacting fixed point at sufficiently large number of flavours opening up to
a second ultraviolet conformal window in the number of flavours vs colours
phase diagram. We first review the state-of-the-art for the large $N_f$ beta
function and then estimate the lower boundary of the ultraviolet window. The
theories belonging to this new region are examples of safe non-abelian quantum
electro dynamics, termed here {\it safe QCD}. Therefore, according to Wilson,
they are fundamental. An important critical quantity is the fermion mass
anomalous dimension at the ultraviolet fixed point that we determine at leading
order in $1/N_f$. We discover that its value is comfortably below the bootstrap
bound. We also investigate the abelian case and find that at the potential
ultraviolet fixed point the related fermion mass anomalous dimension has a
singular behaviour suggesting that a more careful investigation of its ultimate
fate is needed.
