Following the Moore's law the semiconductor industry has delivered continuous increase of systems functionality and speed over the last 50 years through the aggressive downscaling of the transistors. In the last 20 years the UK IC-design based industry has grown to a level of national and international importance. While IC designers in the past enjoyed the freedom that all transistors in a chip could be treated identically, this is no longer the case for the nano-meter sized transistors used in the present and future technologies. Statistical device-to-device variation is introduced by the discreteness of charge and granularity of matter and is inversely proportional to gate area, so that its impact on circuits increases with the reduction of transistor dimensions. When the number of logic gates in a system increases and the architecture becomes more complex, the tolerance to variability is greatly reduced. Even if two devices were identical after fabrication, they could suffer from different aging during operation, causing a time-dependent variability (TDV). TDV is becoming a major threat to the correctness of electronic systems, but there are no tools for its verification because of the lack of a complete understanding. The aim of this project is to carry out an in-depth investigation of the defects and mechanisms responsible for TDV and, based on that, to develop a test-proven TDV simulator, allowing IC designers to assess the impact of TDV on their circuits. The researchers at Glasgow University have pioneered variability simulation and the researchers at Liverpool John Moores University have specialised in experimental characterization of defects. Their highly complementary skills bring them together and make them well positioned to tackle this challenge. By working together with UK companies, the impact of their work on UK industry will be direct. The collaboration with IMEC and its industrial consortium also opens an effective impact pathway on an international scale. The successful control of TDV will deliver reliable electronic products and minimize their power consumption.