Flight Manual - a document prescribed by ICAO primarily for use by flight crew. The manual sets out the limitations, recommended procedures and information necessary for the safe operation of the associated aircraft in accordance with the current airworthiness requirements and air navigation legislation.
The Flight Manual as approved by the CAA, forms part of the Certificate of Airworthiness.
Note: Under EASA the Certificate of Airworthiness must be carried in the aircraft on all flights. It would appear this includes the Flight Manual as it is part of the C of A!
Pilots Operating Handbook (POH)- This is required by Permit to Fly aircraft which do not need a Flight Manual.
Reference: CAP396 Registration and Maintenance of Aircraft.
BCAR Section A, Ch A7-2 and Section B Ch B7-2.