The structure of generalised Lie-Backlund symmetries for the coupled equations of Langmuir solitons are analysed in detail. The form of these symmetries, when compared with those of the conservation laws, yields the first symplectic form. The spectra gradient method is then seen to generate the recursion operator for these symmetries which, on factorisation, leads immediately to the second Hamiltonian structure. The same recursion operator, when used along with the (x,t)-dependent symmetries, yields a new class of generalised symmetries for the equations under consideration. Lastly it is observed that these symmetries are in involution with respect to a Jacobi bracket.