Neoclassically driven tearing modes cause a severe limitation to high b fusion plasmas, unless avoided or controlled. A further extension of the present database with respect to the poloidal ion gyro-radius r*pi and the normalized collisionality nii has been investigated on JET and ASDEX Upgrade. The two most established theories, the ion polarisation current model and the c^ = c|| model, both allow a r*pi scaling for the onset with some weak dependence on the collisionality nii.