The blockade of Brest of 1803-05 is covered in two volumes and concentrates on the achievements of the Hon William Cornwallis and his captains.

Leyland was of the opinion that the work of the blockaders was 'more important and more successful than that of Nelson at the same period'. More succinctly these volumes contain material concerning operations under Cornwallis' command, which geographically included Lorient, Rochefort, Ferrol, the Bay of Biscay and further to the west.

Other important individuals who had a controlling hand in these operations included Lord Keith, Sir James Saumarez, Sir Edward Pellew and Sir Sidney Smith, although only a small number of papers from these individuals are included in this selection.

The selection of letters concentrates on the system of blockade used by Cornwallis, particularly the tactics he adopted and the close management of Lorient and Rochefort.

The importance of ships returning to Britain from the West Indies was paramount but Cornwallis' failure to capture any noteworthy French warships is lain at the door of the lack of frigates. The documents are mainly from the Public Record Office (now the National Archives) and are supplemented by records from French archives.

This volume runs from June 1804 to the end of 1805. It includes amongst many events: Capt. Puget's plan for burning the French fleet in Brest, which was modified by Capt. Brisbane but never sanctioned by the Admiralty Board.

Whilst blockaded Napoleon gave instructions for his men to be kept busy, even though his training suggestions were punitive; Napoleon's grander plans to break the blockade, his operations in Ireland and the West Indies; Cochrane's involvement with the Spanish preceding the secret convention between Spain and France on 4 January 1805 and the cessation of the close blockade gave France the ascendancy.

Gantaeaume's actions after taking command of operations was faced with a grandiose scheme prepared by Napoleon, but it was the latter's order which prevented any great success by continuing with Villeneuve and breaking the blockade.

Disagreements between the top level of management can be seen during 1805 when pressure was intensifying on both sides, especially when Villeneuve escaped from Toulon. Papers showing Villeneuve's subsequent engagement with Calder, as well as Cornwallis's decision to divide the fleet, and Villeneuve's failure to accomplish Napoleon's strategy, provide a picture of the run up to Trafalgar and the run down of the blockade after the battle.