  We demonstrate the impact that present lepton flavour and CP violation data -
neutrino oscillations, baryon asymmetry of the universe, flavour violations in
charged lepton decays and lepton electric dipole moments - have on
supersymmetric seesaw theories by analysing the class of models based on a U(1)
flavour symmetry. The fermion U(1) charges are determined to a large extent by
the data, the flavour patterns being naturally defined through their choice.
The selected models generically predict mu -> e gamma within the reach of the
projected experiments, which could be sensitive enough to exclude the whole
class of them. By now, the present sensitivity to mu -> e gamma already
provides stringent bounds on the contribution of the seesaw couplings to the
lepton electric dipole moments.
