The blue flag is shown to backmarkers advising them to let the lead cars go past.

If a car is being lapped they are not considered to be racing against the cars coming through and therefore they need to let them through without impeding them.

During Free Practice or Qualifying, the blue flag is shown to a car that may hinder another car on a fast lap.

Ignoring this flag more than three times can result ina penalty.

Andrew Burden

The author Kiwi F1 Fan