In Operation Starlight, Group Captain Brail was a ex-R.A.F. officer who ended up managing the air operations of Luftmann's illicit air transport service which specialised in transporting contraband and people across borders without customs formalities.
After his retirement from the R.A.F., Brail had started gambling and had incurred heavy debts. Luftmann approached him and offered him a job which appeared to be easy money at first. All he had to do was manage a "station", a secret base on the southern fringe of the Ashdown Forest where the transport aircraft used by the Luftmann's gang were kept. Unfortunately for Brail, Algy penetrated the operation as an ex-R.A.F. pilot named "Mason" and learnt the location of of the safehouse. Later, Biggles flew into the "station" and had Brail arrested.
Brail turned Queen's Evidence and got off with a light sentence. He provided police with valuable details about the gang's operations, including the procedure for communicating with the gang leader, leading ultimately to Luftmann's arrest.