  Britto, Cachazo and Feng have recently derived a recursion relation for
tree-level scattering amplitudes in Yang-Mills. This relation has a bilinear
structure inherited from factorisation on multi-particle poles of the
scattering amplitudes - a rather generic feature of field theory. Motivated by
this, we propose a new recursion relation for scattering amplitudes of
gravitons at tree level. Using this recursion relation, we derive a new general
formula for the MHV tree-level scattering amplitude for n gravitons. Finally,
we comment on the existence of recursion relations in general field theories.
