Parliament Square: Statues

Parliament Square is a historic and symbolic garden area to the west of the Palace of Westminster.

I have walked around it on many occasions and have looked at the various statues, that peer down onto the tourists and passersby, but never really grasped the full range of people immortalised in the square.

Below are the statues, currently, spaced around the square.

George Canning (Foreign Secretary 1807–1809 and 1822–1827; Prime Minister 1827) 
by Sir Richard Westmacott.

Edward Smith-Stanley, 14th Earl of Derby (Prime Minister 1852, 1858–1859 and 1866–1868) 

by Matthew Noble.

Henry John Temple, 3rd Viscount Palmerston (Prime Minister 1855–1858 and 1859–1865) 
by Thomas Woolner.

Duke of York Column

The Unfinished City's lost viewing platform.

I have walked by this memorial, to the Duke of York, countless times and assumed that it was a simple memorial atop a column. However, I was always intrigued by the doorway at the foot of the column, wondering why it was there and where it led. Was it to access an underground tunnel or was it simply a later addition, to act as a kind of cupboard? I needed to find out.