This talk will present recent research from the nanoplasmonics group at Imperial College London. A focus will lie on efficient light harvesting of electromagnetic energy to the nanoscale using metallic and metallo-dielectric hybrid nanostructures, with examples ranging from non-linear nano sources of radiation, large-bandwidth optical sensors, to applications in photovoltaics. While most applications of plasmonics thus far firmly stay on the footing of classical physics, this talk will also present results on the quantised nature of surface plasmons, including a discussion of single surface plasmon interference and non-local effects.