Heating during the early part of the current rise phase gives a low or negative magnetic shear (= r/q(dq/dr)) in the centre of JET plasmas. Under these conditions the confinement improves with high additional heating power heating during the current ramp-up phase of the discharge. The reduction in the transport manifests itself as a peaking of the profiles with a large gradient region near r/a = 0.55. The best discharges have no transport barrier at the edge of the plasma (L-mode). This allows central power deposition by the neutral beams in JET. A control of the plasma pressure, using feedback of the additional heating power in real-time, minimises the impact of MHD instabilities. As a result, these discharges achieve the highest D-D neutron rates in JET; Sn=5.6x1016 neutrons/s, with ne0 ≈ 6x1019 m-3, Te0 ≈ 12 keV and Ti0 ≈ 26keV.