In 1805, wealthy businessman Joseph Williamson acquired an area of land in Mason Street, Edge Hill, Liverpool, which was then a largely undeveloped outcrop of sandstone with a scattering of scars from small-scale quarrying.

[6] In August 1867 the Liverpool Porcupine described the tunnels as being "a great nuisance" because drains ran straight into them, in one place creating a cess pool full of offensive water 15 feet (5 m) deep, and they were being used for dumping refuse,[7] including down chutes built into the buildings above for the purpose.

In 1881, the North Staffordshire Institute of Mining and Mechanical Engineers conducted a field trip to Liverpool during which they surveyed some of the surviving excavations, producing a plan and dog-leg section of the main parts of the site.

The map also showed the course of the London and North Western Railway cutting between Edge Hill and Lime Street stations which ran through the area.

[10]Both societies eventually acquired the rights to begin digging, and over time a considerable portion of Williamson's legacy has been rediscovered and cleared of the last two centuries' accumulated spoil and rubble.

Williamson's own explanation was reputed to be that his motive was "the employment of the poor"; his workers "all received a weekly wage and were thus enabled to enjoy the blessing of charity without the attendant curse of stifled self respect".

By way of example, at the Mason Street site a beautifully-constructed stone arch was recently uncovered in an otherwise plainly-constructed side chamber, deep underground, with no obvious explanation for its purpose.

However, while Stonehouse called the works "stupendously useless", Hand concluded that Williamson's philanthropic purpose was a noble one and felt he "should have been both pleased and proud to have known him.

[citation needed] More recent research by academics at Edge Hill University has concluded that the 'tunnels' were in fact the result of work by Williamson to restore ground levels after quarrying.

[20] Most of the excavations are directly within a band of high-quality sandstone and show clear signs of having been carried out using established quarrying techniques designed to produce single large pieces of stone suitable for building use.

[21] The tunnels had, therefore, originally been unregulated "slot quarries" for sandstone, used for prestige buildings in the rapidly-expanding Liverpool of the Georgian era, and by subsequently vaulting them over Williamson was able to restore ground levels, facilitating his extensive housing developments on the site.

[21] It seems possible that his secrecy was at least partly driven by a need to conceal his avoidance of both large amounts of income tax and mineral rights duties due to the West Derby Waste Commission from the sale of sandstone.

[21] Despite retiring from the tobacco trade in 1818, Williamson left an estate valued at £40,000 – the equivalent of around £3.3 million in 2019 – and it appears that a large proportion of this income must have come from his excavations and subsequent property development.

Its aim is to promote interest in the life and philanthropic achievements of Joseph Williamson and takes the form of talks, tours, publications and educational visits.

[31] FoWT's main base on Mason Street is the site of Joseph Williamson's house, largely demolished except for a small section of the facade which remains standing.

A second section of tunnels is accessed from the "Paddington" site, comprising a series of underground galleries on several levels, leading to a large vaulted chamber approximately 40 feet (12 m) high from floor to ceiling.