By the 1780s the Royal Dockyard at Portsmouth had become the largest naval base in England, eclipsed in the early 1800s by Plymouth. From the 1760s plans were made to develop the yard to take account of its growing operational significance and these were carried out under the supervision of Charles Middleton, 1st Baron Barham (1726-1813), who as Comptroller of the the Navy Board from August 1778 to March 1790 had overall command of the navy's civil organisation.

The present sketch book, whose size and binding matches that of those among the Middleton papers, now held at the National Maritime Museum, Greenwich, was probably used by Charles Middleton as a convenient way of assessing the progress of the building alterations as he walked around the dockyards. It contains an overall plan of the yard, including the sites of present and proposed buildings, drawn between 1784 - when the range of three storehouses was completed - and 1798 - when the docks were enlarged from two to three basins. A watermark (Heawood 221) dates the paper circa 1789