The spectral response of PHT-0044 (blue) and BCF-20 (green) scintillating fibres was measured as a function of wavelength using a UV LED. It was observed that significant spectral strength from the PHT-044 fibres was missing compared to manufacturer's specifications at the origin of the source, shifting the peak value of the spectrum to significantly higher values in wavelength. In contrast, the corresponding shift for the BCF-20 fibres was minimal. The mechanisms responsible for the observed behavior are discussed herein. Moreover, the attenuation length for each fibre type was extracted and studied as a function of wavelength. Finally, the measured fibre spectra were convolved with the wavelength response from a typical bi-alkali photo multiplier as well as a green-sensitive silicon photo multiplier, yielding the number of photoelectrons, which is shown to be consistent with the numbers extracted from cosmic-ray and photon-beam data.