How Bletchley Park intelligence reached patrol aircraft

How much Bletchley Park intelligence was available to patrol units searching for U-boats?

Crews generally did not see raw intelligence; higher command used it to issue innocuous tasking that put them in the right area.

Sensitive Bletchley Park information remained high in the command chain. Commanding officers received the intelligence and passed down operational directions stripped of their revealing origin, so an aircraft arrived in the right area without its crew knowing the source. The method protected signals intelligence while still turning it into anti-submarine action.