The MHD spectrum of circular cross-section tokamak plasmas with small aspect ratio is studied for low mode numbers. Particular attention is given to the continuous part of the ideal MHD spectrum of such plasmas. Poloidal mode coupling in finite aspect ratio tokamaks yields gaps in the Alfven continuum. Global Alfven modes are found with a frequency inside these gaps. By interaction with the continuum branches the global Alfven modes experience clamping via phase-mixing. This clamping is computed in resistive MHD. asymptotically small resistivity the clamping is finite and independent of h.