  We present estimates of parameters which model the primordial density
fluctuations using CMB data from the VSA, 1st year WMAP, CBI and ACBAR along
with external priors from 2dF and the HST. Taken at face value there is
significant evidence for a running spectral index when only scalar fluctuations
are considered. The significance of this result is increased by the inclusion
of tensors and, although the result is weakened by the inclusion of `running of
the running', the basic trend toward significantly negative running remains. We
discuss the implications of this result and how it might be strengthened by
future observations.
