Alexander Allan was a Glasgow manufacturer and one of the first persons to take up residence in the newly established village of Bridgeton c.1776. His new estate of Newhall lay close to the banks of the River Clyde, just downriver from Rutherglen Bridge, but it annoyed Allan that he did not have direct access to the riverside from his property due to the existence of a public footpath. This path had been in use from time immemorial, but Allan was determined to have his way.
He caused an earthworks to be raised over the path thereby extending his property down to the riverside itself. These works were strongly reinforced with stone walls and turfed over. To facilitate the continued use of the walkway, which otherwise would have been completely blocked, he had an arched tunnel built through these works. This tunnel was about 8 feet high by 8 feet wide and became known as Allan's Pen.
Both the pen and the presumption of its builder were very much resented by the local people who saw it as an curtailment of their right of access to the riverbank. No direct action was taken against the structure, but in protest the weavers refused to undertake any work for Allan even when he increased his prices.
The matter was finally resolved by the forces of nature and the low lying geography of the locale. The winter following its construction saw the pen and earthworks mostly swept away by the ice-laden, flooding river. Allan made little attempt to repair the damage done and the pen became little more than a memory.
Many years later, supposedly at the instigation of a descendant of Allan, a tablet was set into a wall in the vicinity which was inscribed, "The Site of Allan's Pen." This now remains as the only evidence of those remote events. Some ruins were still evident as late as 1938, but these have all been removed and the area landscaped as part of the Clyde Walkway.
Allan's Pen was one of the earliest attempts by the riverside landowners to hinder the public's right of access to the banks of the Clyde. The most famous of these, and the one which halted any further efforts, was the case of Harvey's Dyke.