  The recent results of the PIBETA experiment strongly suggest the presence of
a non-(V-A) anomalous interaction in the radiative pion decay. The same
interaction should inevitably contribute to the neutron decay and in particular
it should affect the V_ud determination. This paper is dedicated to the
prediction of the eventual discrepancy in V_ud extracted from the super-allowed
Fermi transitions and from the polarized neutron decay.
