This paper presents an analysis which happens to be an extension of the previous study (1999) of the authors on subcooled inverted annular flow film boiling. A physical model for constant heat flux condition at the wall of a vertical tube with vapour film at the periphery and liquid in the core region is considered in the analysis. Employing Levy's (1960) postulation a relationship between the system parameters and the dryness fraction is obtained and subsequently utilized in the development of the theory for inverted flow film boiling. Further, using Van Driest (1956) mixing length theory velocity and temperature profiles are evaluated to establish the local heat transfer coefficients. A correlation is proposed to predict the mean heat transfer coefficient for constant heat flux conditions of the tube wall.