Abstract: A filling pipe for a fuel tank comprises a housing which has, on its inner circumference, a number of inwardly directed threaded segments and at least one vertical indentation, the upper part of the housing has segmented threaded parts for screwing a closure cap therein, and its lower part, which is contracted to the diameter of the filling pipe, contains an insert. The insert has, on its outer circumference, a number of outwardly directed threaded segments and two outwardly directed lugs, the segments together with the inwardly directed threaded segments of the housing holding the insert in the longitudinal direction, and the lugs together with the at least one indentation form a safeguard against twisting.