The Arnold Hague database of FN convoys: The FN series of convoy ran from the Thames (Southend) to the Firth of Forth (Methil) and ran throughout the war from September 1939 to May 1945. The route was protected by defensive mine fields but was vulnerable to attack by U-boat, E-boat, aircraft and enemy mines.
Note that Hague used his own numbering system for this series. In fact, FN convoys were numbered 1 - 100 in repeating phases. Note also that Hague's records for this series is far from complete.