ESDU 88035 introduces a Fortran program provided on disc in the software volume (ESDUpac A8835) both uncompiled and compiled within ESDUview@ a user-friendly interface that prompts on-screen for input data and runs under MS DOS. The program calculates the applied bending moment that gives a maximum allowable extreme fibre stress in a beam under symmetric loading. The program includes the non-linear elastic behaviour beyond the limit of proportionality using the generalised stress-strain curve of ESDU 76016. A form factor based on an elastic stress equivalent to the 0.2 per cent proof stress is also given. The beam section may be any multi-segment polygon provided its first and second moments of area are balanced about the neutral x-axis (the axis about which the moment is applied). Details of the input format@ the output interpretation and special warnings are provided@ and two practical worked examples illustrate the use of the program.