Nathaniel John Fenner was an oil merchant who owned a wharf in Millwall on the Isle of Dogs, London in the nineteenth century. Along with Robert Fairlie he came up with idea of developing the Millwall Docks. He first asked Fairlie to draw up a plan to develop the empty land behind his wharf.
In 1856 with Henry James Fenner, Nathaniel had taken out a lease on a plot of undeveloped land which had previously been used as a garden and paddock, in Southern Millwall. Here they erected a two-storey wharehouse. Having experienced difficulty when attempting to land cargoes at low tide, Fenner hit on the idea of a enclosed non-tidal docks for wharfingers created by building a 'canal' across the Isle of Dogs provided with entrance basins at each end and a central arm which would extend north towards the East and West India Dock Company's Timber Pond.
Following the insolvency of the Millwall Iron Works, Ship Building & Graving Docks Company, the Fenner's took over the Nast House, which that company had previously occupied. From 1877 they used this premises for storing barrels of petroleum. They converted the Mast House, and erected brick internal walls. Also they sank a large pit where the Mast Pond had been, where they stored more barrels of petroleum.
- Stone, Peter (2017). The History of the Port of London: A Vast Emporium of All Nations. Barnsley: Pen and Sword. ISBN 9781473860407.
- "Southern Millwall: The Byng Estate in Southern Millwall | British History Online". www.british-history.ac.uk. British History Online. Retrieved 7 April 2019.
- Guillery, Peter (1990). "Building the Millwall Docks" (PDF). Construction History,. 6.
- "Southern Millwall: Drunken Dock and the Land of Promise | British History Online". www.british-history.ac.uk. Retrieved 7 April 2019.