O(a) improvement of nucleon matrix elements

We report on preliminary results of a high statistics quenched lattice QCD calculation of nucleon matrix elements within the Symanzik improvement programme. Using the recently determined renormalisation constants from the Alpha Collaboration we present a fully non-perturbative calculation of the forward nucleon axial matrix element with O(a) lattice artifacts completely removed. Runs are made at β = 6.0 and β = 6.2, in an attempt to check scaling and O(a2) effects. We shall also briefly describe results for ⇄χ↩, the matrix element of a higher derivative operator.