  This letter studies the Sp(2) covariant quantisation of gauge theories. The
geometrical interpretation of gauge theories in terms of quasi principal fibre
bundles $Q(M_S, G_S)$ is reviewed. It is then described the Sp(2) algebra of
ordinary Yang-Mills theory. A consistent formulation of covariant lagrangian
quantisation for general gauge theories based on Sp(2) BRST symmetry is
established. The original N=1, ten dimensional superparticle is considered as
an example of infinitely reducible gauge algebras, and given explicitly its
Sp(2) BRST invariant action.
