[Show thumbnails] _The SI ampere is expected to be redefined, away from a definition based on mechanical forces, to a definition based on the fundamental charge. We aim to support future primary electrical metrology based on single-electron devices. Our objectives are: To develop single-electron-based current sources reaching a current level of ≈1 nA with an uncertainty at, or below, 1 part in 107. To test the universality, robustness and reproducibility of single-electron-based current sources for the practical realisation of the new SI ampere. To implement high-accuracy current measurement capability across NMIs, suitable for the testing of various types of single-electron devices. To develop guidelines for testing the accuracy of single-electron-based current standards. To facilitate the take up of the technology and measurement infrastructure developed by the project by the measurement supply chain (accredited laboratories, instrumentation manufacturers) and end users (industries where small-current measurements at pico-ampere and femto-ampere levels are required).