History of Big Ben
In 1844, Parliament decided that the new buildings for the Houses of Parliament, by then under construction, should incorporate a tower and clock. The commission for this work was awarded to the architect Charles Barry.

The largest bell ever cast in Britain up to that time had been 'Great Peter' at York Minster. This weighed just 10¾ tons, so it is not surprising the bellfounders were wary of bidding for the contract to produce the new bell, particularly since Denison insisted on his own design for the shape of the bell as well as his own recipe for the bellmetal. In both respects his requirements varied significantly from traditional custom and practice. Eventually, a bell was made to his specification, albeit somewhat oversize at 16 tons, by John Warner & Sons at Stockton-on-Tees on 6th August 1856, but this cracked irreparably while under test in the Palace Yard at Westminster. It was then that Denison, who now had QC after his name, turned to the Whitechapel foundry....

One final point of interest is that the transcript mentions the lawyer for the Foundry using a small model to demonstrate the principles of bell-casting. This would almost certainly have been the same small, exquisitely crafted model currently on display in the Foundry's lobby museum area

Big Ben remains the largest bell ever cast at Whitechapel. Visitors to the foundry pass through a full size profile of the bell that frames the main entrance as they enter the building. The original moulding gauge employed to form the mould used to cast Big Ben hangs on the end wall of the foundry above the furnaces to this very day.