  The magnitude of the CKM matrix element Vub is determined by measuring the
inclusive charmless semileptonic branching fraction of beauty hadrons at OPAL
based on b -> Xu l nu event topology and kinematics. This analysis uses OPAL
data collected between 1991 and 1995, which correspond to about four million
hadronic Z decays. We measure Br(b -> Xu l) to be (1.63 +/- 0.53 +0.55/-0.62) x
10^(-3). The first uncertainty is the statistical error and the second is the
systematic error. From this analysis, Vub is determined to be:
  |Vub| = (4.00 +/- 0.65(stat) +0.67/-0.76(sys) +/- 0.19(HQE)) x 10^(-3).
  The last error represents the theoretical uncertainties related to the
extraction of |Vub| from Br(b -> Xu l) using the Heavy Quark Expansion.
