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 Richard Osman.

Rachel Riley, JB Gill, Katie Derham and Richard Herring take on a series of challenging quiz games across one week, selected by host and teatime quiz favourite Richard Osman.

Over five days, Rachel Riley, JB Gill, Katie Derham and Richard Herring take on a series of challenging quiz games selected by host and teatime quiz favourite Richard Osman.

Over five days, Rachel Riley, JB Gill, Katie Derham and Richard Herring take on a series of challenging quiz games selected by host and teatime quiz favourite Richard Osman.

Rachel Riley, JB Gill, Katie Derham and Richard Herring take on a series of challenging games selected by teatime quiz favourite Richard Osman. The week's champion is crowned.