The primary objective is to determine Lp-PLA2 activity in atherosclerotic carotid plaques after 14 (+/-4) days treatment with darapladib, compared to placebo. Secondary objectives include determination of the change in Lp-PLA2 activity in blood, Lp-PLA2 mass in blood and plaque, specified biomarkers in blood and plaque and their respective correlation's with Lp-PLA2. In addition, the study aims to characterise the PK/PD of repeat oral doses of SB-480848, and safety and tolerability in this population.