The Photochron 5 Streak Tube was designed at St Andrews University by Professor W Sibbett & et al. In its original form, the tube had four times magnification and was calculated to have a temporal response of circa 250 fs. Prototypes made by Photek were tested and showed temporal resolution of 400 fs. The electron optical design of the tube has been recalculated, which enables the tube to be operated at magnification as low as 2, to take advantage of advances in CCD design and photon counting/centroiding technology. We also studied the theoretical possibility of operating the tube with a small slot and no mesh. This would enable a gain in quantum efficiency inversely proportional to mesh transmission -- i.e. a factor about 1.5 times improvement. The focus is intensely anisotropic, with magnification x 2.6 in the spatial axis and 1.3 in the temporal axis. The working area of the tube is considerably reduced, to less than 100 microns width. A second iteration of the anisotropic design has been built and tested. Magnification in the spatial direction is x 2 and x 1 in the temporal direction. Working area is approximately 1.5 mm x 12 mm. The low magnification in the temporal direction can be used to increase the working area of the tube, so increasing light throughput and dynamic range, without effecting time resolution. Alternatively, time resolution can possibly be improved, providing that the readout spatial resolution can take advantage of this factor.