Over the last few years metal halide perovskites have risen to become a very promising PV material, captivating the research community and expanding into significant industrial effort. In the most efficient devices, which now exceed 22% solar to electrical power conversion efficiency, the perovskite is present as a solid polycrystaline absorber layer sandwiched between n and p-type charge collection contacts. Beyond efficiency, long-term stability is of critical importance. Within the thin film device there exist up to six discrete material layers, in addition to the perovskite absorber layer, all of which could degrade under operation, or induce degradations to their neighbouring layers. In this talk, I will present the key steps and key challenges which we have overcome on the path from mesostructured hybrid solar cells which would only last a few hours under continuous operation, to robust thin-film perovskite solar cells capable of surviving for 1000’s of hours under rigorous stressing. I will specifically present recent work on more stable charge extraction layers and perovskite absorber layers, which deliver “non-degrading” solar cells, stressed under elevated temperature full spectrum light soaking. I will finish by presenting a brief summary the efforts by Oxford PV Ltd which have enabled the perovskite technology surpass the International Electrotechnical Commission stability tests.