Backmarker is the name given to the drivers at the rear of the The field is a reference to the full grid of cars, from pole to the backmarkers. Consider it in the... There's more... when they are about to be caught by faster cars and lapped.
Backmarkers are shown a The blue flag is shown to backmarkers advising them to let the lead cars go past. If a car is... There's more... requiring them to let the faster cars through.