  The symplectic implosion construction of Guillemin, Jeffrey and Sjamaar
associates to a Hamiltonian action of a compact group K on a symplectic
manifold X its 'imploded cross section'. When X is a complex projective variety
and K acts linearly on X, this construction is closely related to geometric
invariant theory (GIT) for the action on X of a maximal unipotent subgroup U of
the complexification G of K. The aim of this paper is to generalise symplectic
implosion to give a symplectic construction for GIT-like quotients by unipotent
radicals U of arbitrary parabolic subgroups P of the complex reductive group G
acting linearly on the projective variety X.
