Normalised correlation matrix of the parameters computed from the VIPERS Markov chain. The blocks represent the mean density, galaxy bias, power spectrum and RSD parameters. The structure in the covariance arises from the data model parameterisation. The values of luminosity and colour dependencies of galaxy bias and mean density within a redshift bin are strongly correlated, while they are only weakly correlated across redshift. On large scales the power spectrum covariance is diagonal, but at k> 0.3h Mpc^-1the bins become correlated owing to coupling of the small-scale power with the redshift-space distortion parameters.