The towers were built by the civil engineering firm who built the Kingsway tunnel directly below each structure, Edmund Nuttall Limited (now known as BAM Nuttall Limited). The fact that they were built by engineers rather than architects means that the buildings cannot be contributed to a single architect or even set of architects, just to a anonymous set of engineers therefore there is not a name associated with the buildings other than that of the engineers. The two towers are unlisted but unlikely to be threatened with demolition as they still carry out there original purpose and replacing them would be very expensive.
Also on the Mersey are a set of earlier ventilation shafts completed in 1934 for the Queensway tunnel, the original road tunnel across the Mersey. These are a stark contrast to the Brutalist towers of the 1970's, those on the Liverpool front are faced in stone whilst those on the Birkenhead front are faced in a dark brick. The fact that the two new towers are similar and not completely different like the previous towers of the 1930's demonstrates to my mind a more egalitarian partnership between the two sides of the river as they are treated equally (instead of the expensive stone for prosperous Liverpool and cheap brick for the less affluent birkenhead side).