  By studying the total fusion and breakup cross-sections in the interaction of
the neutron-halo $^{11}{\rm Be}$ projectile on the lead target $^{208}$Pb, it
is shown that, even for the neutron-halo projectile, the breakup channel
remains the most dominant reaction channel at sub-barrier energies, following a
characteristic behavior that was also previously verified for the case of the
proton-halo projectile $^8{\rm B}$. This feature is found to emanate from the
enhancement of the breakup cross-section, due to the continuum-continuum
couplings coming exclusively from its Coulomb component. We further speculate
that the enhancement of the Coulomb breakup cross-section at sub-barrier
incident energies by the continuum-continuum couplings could be associated with
the projectile breaking up on the outgoing trajectory, provided these couplings
can be proven to delay the breakup process.
