The prolonged war with Revolutionary France began in 1793 yet, for the first fifteen years of its duration, was predominantly a conflict fought out at sea. Only after the British Expeditionary Force under Wellington landed in Portugal in August 1808, to begin the so-called Peninsular War, did full-scale operations begin in earnest on land and, in one of those which followed soon afterwards, the Royal Navy played a particularly prominent role.
This was the campaign against Walcheren, an island in the estuary of the river Scheldt which the French had garrisoned heavily and which they were using as a highly effective naval base for their activities in the Channel and the North Sea. The Admiralty and the Army high command had taken the decision to mount an offensive expedition against it in May 1809 but because its departure was delayed until 28th July, all element of surprise was lost and the venture was doomed from the start. Despite a powerful force of 235 naval vessels of all kinds, including 15 ships-of-the-line led by H.M.S. Blake and 40 large transports carrying over 39,000 troops, which entered the Scheldt on 11th August (1809), the French had already withdrawn all their ships up-river and placed them behind a protective heavy boom. Although the troops did manage to capture both Walcheren and Flushing, albeit for only a short time, a serious outbreak of fever soon decimated their numbers and none of the expedition's objectives - to capture all French shipping in the area and destroy the dockyards and installations at Flushing, Antwerp and Terneuzen - were achieved.