JET has recently reached fusion relevant plasma parameters. An overview of the project is given showing the enhancements, that have been made and which have lead to the improved performance. The limits of the key parameters: n, β and τE will be presented and it will be shown that the central values of density n and temperature T are crucial. Ways to improve these will be discussed. The presentation of the presently obtained high fusion parameters will be followed by a discussion on results to be expected with D-T operation.