A major improvement of a technique for the acceleration of ultrashort, multi-MeV electron bunches by laser-driven surface plasma waves has been experimentally demonstrated. By focusing the laser on the short edge of a thin target, surface waves are excited without the need of engraving the target. Simulations clarified the mechanism for electron injection and also the unexpected role of layers of surface contaminants, which modify the surface wave profile and propagation distance favoring more efficient acceleration. The experiment has been lead by a team from the Queen’s University of Belfast. The CNR/INO researcher Andrea Macchi contributed to the experimental design and the theoretical framework. The results were published in Physical Review Letters (highlighted as Editor’s suggestion) with a synopsis appearing in Physics Magazine.