During this time, he developed strong sympathies with the neglected downtrodden section of the community and he campaigned against terrible living conditions of his patients and to improve the sanitation of Liverpool.

Duncan challenged the commonly held conception that it was the fault of the poor themselves that they became ill, he viewed social poverty as the cause, not individuals and looked to things like improving housing and sanitation to help the situation.

His evidence is given in vol 2, 31st August 1840, where Duncan remarked, “There can be little doubt that the causes of the unusual prevalence of this disease in Liverpool are to be found principally in the condition of the dwellings of the labouring classes, who are almost exclusively its victims; but partly also in some circumstances connected with the habits of the poor.

The lecture was also published as a pamphlet which had an immediate effect upon the Council, who realised that something had to be done.Council Minutes 2nd August 1843 ‘…they have been deeply impressed by the novel and appalling statements made in a pamphlet recently published by their respected and able Townsman Dr W H Duncan by which it appears that Liverpool so far away from one of the healthiest as they had thought is actually the most unhealthy town in England owing to the extreme density in which the lower classes of its population are crowded together in confined Courts and Cellars constructed without due regard to ventilation and drainage and without adequate arrangements for the removal of filth.’His lecture and pamphlet effectively inspired the Council to compile and pass the Liverpool Sanitary Act 1846, which in turn, acknowledged that a medical person was needed to tackle the many complex issues.

He had to organise a Public Health Department from scratch and lay down rules of administration and procedure, train staff and fit himself and activities into the framework of the Town Council organization.

One of Duncan’s first challenges faced as Medical Officer for Health came with the influx of immigrants arriving in Liverpool due to the Great Famine of Ireland.

With a steady rise of ‘pauper immigration’ Liverpool saw previously vacated cellars once again used out of desperation - causing cholera and typhus to spread rapidly.

A modified system of quarantine was adopted in July 1847, but he recorded that the only practical effects of this were to transfer those actively suffering with fever to the Hospital ships on the Mersey.

Perhaps the most important of these steps – and there were many of them – were housing, education, personal hygiene, National Health Insurance, and a general improvement in the standard of living.

He made use of the powers of the Sanitary Act to enforce necessary improvements in sanitation and dwellings, involving the magistrates to persuade owners to take corrective measures.