The morphometric characteristics of the retinal vascular network have been associated with risk markers of many systemic and vascular diseases. However, analysis of data from large population based studies is needed to help resolve uncertainties in these associations. QUARTZ (QUantitative Analysis of Retinal vessel Topology and siZe) is a fully automated retinal image analysis system that has been designed to process large numbers of retinal images and obtains quantitative measures of vessel morphology to be used in epidemiological studies. QUARTZ has been used to process retinal images from UK Biobank which is a large population-based cohort study. In this paper, we address issues of robustness with respect to processing large datasets and validate QUARTZ using a subset of 4,692 UK Biobank retinal images. Ground truth data produced by human observers for validation have been made available online. Following validation, 135,867 retinal images (68,549 participants) from the UK Biobank study were processed by QUARTZ. 71.53% of these images were classified as being of adequate quality, which equated to 80.90% participants with at least one image of adequate quality. The vessel morphometric data are currently being used in epidemiological studies. The intention of the UK Biobank Eye and Vision Consortium is to include these derived measures in the UK Biobank data archive.