  In bilinear R-Parity violating models where a term \epsilon_3L_3H_2 is
introduced in the superpotential, the tau lepton can mix with charginos. We
show that this mixing is fully compatible with LEP1 precision measurements of
the Z\tau\tau and W\tau\nu_\tau couplings even for large values of \epsilon_3
and of the induced vacuum expectation value v_3 of the tau-sneutrino. The
single production of charginos at e+e- colliders is possible in this case and
we present numerical values of the cross-section at LEP1, LEP2 and an NLC. We
find maximum values of 10 pb at LEP1 and 1 fb at NLC, while the corresponding
values at LEP2 are too small to observe.
