Rachel Riley, JB Gill, Katie Derham, and Richard Herring (5/5)

Every day this week the celebrity contestants - mathematician Rachel Riley, singer and farmer JB Gill, newscaster Katie Derham and comedian Richard Herring - take on a series of challenging quiz games selected by the host, teatime quiz legend Richard Osman. A daily winner is declared following a quick-fire round at the end of each show as the scores are tallied across the week, resulting in an overall champion being crowned on Friday. Will the winning star opt for the much coveted House of Games sparkling wine, or instead go for the must-have Richard Osman action doll?