Fibre reinforced polymer (FRP) composites are the go-to material for structural applications where weight is crucial. Predictions about bulk components are often based on micro-mechanical models, typically through a multi-scale modelling framework (bridging the gap from fibre scale (± 10 μm) to ply scale (±100 μm) to laminate scale (± 10 – 100 mm and beyond)). Much more fundamental insights and measurements at the micro-scale are necessary to enable fully predictive multi-scale modelling and faster adaptation of FRP. Therefore, we propose the development of advanced micro-mechanical test methods for fibre reinforced polymer composites based on in-situ optical and electron microscopy during loading. This includes micro-scale Digital Image Correlation (DIC) which gives full-field strain information at the sub-micron scale, force measurement and correlation of the damage mechanisms at micro- and macro-scale. This also generates accurate input data for multi-scale models for composites.