Around 1850, the era of stage-coaches was ending and rail transport was just beginning. During this period, a thriving trade existed between the East Coast of England and the Pool of London below London Bridge. Initially, grain was shipped from the farms of East Anglia to London, while a variety of merchandise, including coal and manufactured goods, was transported on the return journey. The breweries of London had a strong demand for malt, and there was a significant market for straw and oats.

Later, as cheaper wheat was imported into London Docks from Canada, the Continent, the Mediterranean, and Black Sea ports in larger loads, it required trans-shipment into 100-ton consignments for millers on the rivers Stour and Orwell. This need gave rise to a specialized type of vessel capable of coming alongside cargo ships and liners in the Pool of London, navigating the shallow waters of East Anglia, and handling small cargoes economically. This led to the development of the spritsail barge, which created a new industry, a unique class of ship, and a resilient breed of sailors.

The spritsail barges were adaptable, fast, and economical vessels typically manned by a crew of three: a skipper, a mate, and a boy. These men earned modest wages and their keep while sailing, with additional pay for loading and unloading. Often, the crew would manually handle 200 tons of cargo in a single day, working with coal, grain, straw, and manure. To avoid returning under ballast, which could destabilize the vessel in heavy weather, they accepted any available cargo. The barges featured large hatches for easy access during lightering and quick turnarounds. Known for their speed even in light airs, the barge-men honed their skills by racing their vessels. They were also sought after as crew members during the era of J-class yachts.

These flat-bottomed barges were equipped with lee-boards, allowing them to sail close to the wind and near the shore in shallow waters. Although primarily coastal vessels, they were capable of crossing the English Channel when necessary, which explains their involvement in the evacuation of Dunkirk.

Tollesbury is a fishing village in Essex, located on a tributary of the River Blackwater, which served as a loading port for stack barges. These barges could lie alongside for horse-drawn wagons to unload cargo. The barge Tollesbury was named after this village by her owner, Mr. Fisher, in 1901. She was constructed at Feltham's Yard in Sandwich on the Kentish Stour. Her squat profile earned her the nickname "Sandwich Box."

In 1912, Tollesbury joined the fleet of R & W Paul Ltd., renowned wharfingers in East Anglia who traded in grain, malt, and animal feeds. To optimize their fleet, the company also became barge builders. The vessel's skipper was Lemon Webb, who earned his livelihood by transporting stone from the West Country, as well as coal, coke, and pitch from both sides of the Channel during the First World War.

In 1932, R & W Paul Ltd. instructed Webb at Colchester to collect 130 tons of Canadian feed oats at Antwerp. Although his crew had just left the barge, Webb was ordered to find another crew and proceed immediately. Upon returning to Ipswich, Webb reported the successful completion of the task and revealed that he had sailed the vessel single-handedly, having found no crew suitable for the job. This feat demonstrated both his exceptional skill as a sailor and the suitability of the Tollesbury’s design for short-handed sailing without an engine.

At the end of May 1940, while sailing up the Thames near Erith, Webb was approached by a naval launch and directed to Cory's jetty for orders. There, he and his nineteen-year-old crew member were given the option to leave the vessel or volunteer to assist in the evacuation of the British Expeditionary Force (BEF) from Dunkirk. Both volunteered without hesitation.

By mid-afternoon, Tollesbury, along with the larger Ethel Everard of London and towed by the tug Sun XI, joined a diverse armada of pleasure boats, fireboats, tugs, and barges. The plan was to beach the barges to serve as embarkation platforms for troops waiting ashore. From these platforms, soldiers could be transferred to small boats and launches, and eventually to larger transports in deeper water. The wooden hulls of the barges provided relative safety from magnetic mines, and their flat bottoms allowed them to approach the beaches more closely than other vessels.

Arriving at Dunkirk at midnight, the tug released the barges, which were ordered to beach themselves. With little wind, the crew used their 24-foot sweeps (long oars) to reach the shore. As they neared, soldiers warned them of shallow waters. The crew dropped anchor and attempted to provide access with a wooden ladder, which was soon broken by the surge. They then lowered their tender to create a makeshift gangway. A total of 273 exhausted, sunburnt, and wet soldiers boarded the Tollesbury, desperate for food and water. Webb provided water, biscuits, and a few loaves of bread.

Attempts to re-launch the barge were initially unsuccessful due to grounding on the falling tide. Two hours later, the rising tide refloated the vessel, and the crew set sail for deeper water. Progress was slow in the light winds, so they dropped anchor again. The mate, a veteran of naval service in the First World War, signaled a destroyer to request transfer of the troops. An air raid delayed the operation, but the Tollesbury remained unscathed despite bombs and anti-aircraft shrapnel.

Later, a barge attempted to tow Tollesbury off too quickly, causing the towline to snap. Eventually, the vessel sailed for Ramsgate. During the voyage, dive-bombers attacked, dropping bombs close to the barge, but she was spared thanks to the intervention of a destroyer and a motor torpedo boat (MTB) that drove off the attackers. The crew witnessed the sinking of two destroyers and narrowly avoided a mine explosion near the North Goodwins.

At Ramsgate Roads, the soldiers were transferred to motorboats for landing ashore. One soldier remarked to the skipper, "She is a lucky ship," a sentiment that proved true as Tollesbury remains afloat to this day.