Somerset issued provisional orders to British naval units around the world to be prepared to attack American shipping wherever it might be found. The Cabinet was also agreed that establishing and maintaining a tight blockade was essential to British success. In 1864 Milne wrote that his own plan was:  Regarding possible joint operations with the Confederacy, Somerset wrote to Milne on December 15:  Somerset was opposed to attacking heavily fortified positions and Milne concurred:  The British strongly believed that they had naval superiority over the Union. Although Union ships outnumbered Milne's available force, many of the United States fleet were simply remodeled merchant ships, and the British had an advantage in the number of total guns available. Bourne suggested that this advantage could change during the war as both sides turned more to ironclads. In particular, British ironclads had a deeper draught and could not operate in American coastal waters, leaving a close blockade dependent on wooden ships vulnerable to Union ironclads. Of course, the military option was not needed. If it had been, Warren concluded that, "Britain's world dominance of the seventeenth and eighteenth centuries had vanished; the Royal Navy, although more powerful than ever, no longer ruled the waves." Military historian Russell Weigley concurs in Warren's analysis and adds:  Some contemporaries were less sanguine about the U.S. Navy's prospects in a war with Britain. On 5 July 1861, Lieutenant David Dixon Porter wrote to his old friend, Assistant Secretary of the Navy Gustavus Fox:  In February 1862, the Duke of Cambridge, the British Army's commander-in-chief, gave his analysis of British military reaction to the "Trent" affair:  On December 17, Adams received Seward's November 30 dispatch stating that Wilkes acted without orders, and Adams immediately told Russell. Russell was encouraged by the news, but deferred any action until a formal response to the British communication was received. The note was not released to the public, but rumors were published by the press of the Union intent. Russell refused to confirm the information, and John Bright later asked in Parliament, "How came it that this dispatch was never published for the information of the people of this country?" In Washington, Lyons received the official response and his instructions on December 18. As instructed, Lyons met with Seward on December 19 and described the contents of the British response without actually delivering them. Seward was told that the British would expect a formal reply within seven days of Seward's receipt of the official communication.