Optical soliton dynamics can cause extreme alteration of the temporal and spectral shape of a propagating light pulse. Recently we have demonstrated these dynamics in large-core hollow capillary fibres filled with gas. This enables scaling of soliton effects by several orders of magnitude to the multi-millijoule energy and terawatt peak power level. We observe pulse self-compression to sub-femtosecond field waveforms corresponding to high-power optical attosecond pulses. We also efficiently generate high-energy (up to 30 μJ) pulses continuously tuneable from the vacuum ultraviolet (VUV) to near infrared (110 nm to 800 nm) with few-cycle pulse duration across the whole range. This corresponds to the brightest available tuneable light source in the VUV. These results promise to be the foundation of a new generation of table-top light sources for ultrafast strong-field physics and advanced spectroscopy.