Churchgate House pictured in April 2012 (copyright Google Street View). The Royal Oak once stood on this site. A pub with the same name was later situated on Paley Street, which can be seen running by the side of Churchgate House.
The Royal Oak stood on Churchgate from at least the 1770s until it was destroyed by fire on 30 June 1848 killing George Radcliffe, a Breightmet man sleeping there for the night. 
Gordon Readyhough  claims that the location of the pub is unknown but that it was not to be confused with a pub on nearby Paley Street that took the Royal Oak name some time after the original pub burned down. However, in a report for the town’s mayor on Bolton’s sanitation in 1848 - the year the Royal Oak was destroyed - John Entwisle puts the pub in the vicinity of Molyneux’s Yard, the Flaggs and Oliver Lane, all of which stood roughly in front of the site of the current Churchgate House, opposite what is now Hogarth’s, the former Capitol and Boars’s Head pub. 
Bolton’s population stood at around 17,000 in 1801. By 1841 it had grown to almost 50,000 as people moved to the centre of town during the Industrial Revolution to look for work.  Entwisle goes on to describe the sanitary conditions at that time in the dirtiest part of what he had already ascertained was a filthy town.
“In immediate contiguity [to Molyneux’s Yard]…is the Flaggs and
here fever had infested the whole neighbourhood. In the houses behind the Royal Oak there were
several cases; in one the husband had an attack six weeks in duration. In the
next house a family of seven, four of whom had fever, and one died. Immediately
opposite the houses is a necessary in a broken condition, the privy full, and
heaps of ashes and night soil occupied a considerable portion of the yard.
Beyond this heap of refuse is the cesspool of Molyneux’s Yard, only separated
by a wall which is part falling down.”
To give another aspect of life in Bolton in the 1840s Entwisle analysed all the deaths in the town in the five years to 1847 and calculated the average age of death. But in an interesting twist he also calculated the average age of death by social class.
According to Entwisle, 116 “gentlemen and persons engaged in professions, and their families” died at an average age of 51 years. In addition, 614 people he described as “tradesmen and their families” died at an average age of 27 years and 2 months. But “Operatives and their families” died at an average of just 19 years and 6 months.
The outstanding point about this last social grouping – the lowest of the three social classes – was their sheer number: 8142 of them. In other words, over 90percent of the people in the town died before their 20th birthday between the beginning of 1843 and the end of 1847. Of course a lot of them were children – over 50percent of the children of the lower orders died by the age of five – but with an average at death of 19, pubs like the Royal Oak were probably losing almost all of their custom every two years simply due to them dying off.
Fortunately, that part of town was cleaned up and Entwisle’s report perhaps had an impact. It’s available to borrow at Bolton Central Library and makes for grim reading. Running water was laid on in that part of Churchgate. Molyneux’s Yard was swept away although Flaggs and Oliver Lane remained into the 20th-century.
Entwisle couched his arguments in language the mayor and rest of the businessmen that ran Bolton could understand: it was counter-productive maintaining a situation where 90 percent of your workforce failed to reach the age of 20. But this was 1848, a year when revolution was taking hold in Europe and the monied classes in Bolton couldn’t help but look over their shoulder at the potential for social unrest.
Churchgate later became the theatre centre of Bolton with the Grand and the Theatre Royal built on the site of the slum dwellings in the area where the Royal Oak once stood. The theatres made way for offices in the sixties and Churchgate House was built in their place.
 Annals Of Bolton, James Clegg, 1888.
 Bolton Pubs 1800 to 2000, Gordon Readyhough, 2000.
 A Report On The Sanatory Condition Of The Borough Of Bolton, John Entwisle, 1848.
 Wikipedia entry on Bolton, retrieved 12 October 2014. Figures combined for Great Bolton and Little Bolton.