In mid-May 1809, the British government was pretty sure it was going to be sending a sizeable expedition to the Scheldt basin to reduce the island of Walcheren and destroy the dockyards of Antwerp. Horseguards was busily preparing a force of thirty thousand men (the number would later rise to nearly 40,000); the Admiralty was putting together a flotilla of over six hundred vessels, from the 80-gun HMS Caesar to a vast fleet of transports and flatboats. At this point, however, the military and naval commanders had not yet been appointed.
Lord Castlereagh, the Secretary of State for War, had been thinking about an expedition to the Scheldt for months. When he had first considered it, he had intended the command to go to Sir John Moore, but Moore had been killed at Coruña in January. For a while there was a rumour that Sir John Hope would take the command, as he was one of the more senior generals attached to the expedition, and there were other rumours that Sir Harry Burrard and even the Duke of York were considered, In fact the job went to John Pitt, 2nd Earl of Chatham, then a cabinet member as Master-General of the Ordnance.
Why Chatham was chosen mystified contemporaries, and historians since. Chatham had joined the army in 1773, but, although a reasonably senior Lieutenant-General by 1809, had not served abroad since 1799. He had in fact not been militarily active at all between 1784 and 1798. There were the usual conspiracy theories – the King had nominated him; George Canning wanted Chatham to succeed so he could prop him up as a figurehead Prime Minister; Chatham needed the cash – and of course after the whole deal went wrong everyone at Horseguards and the War Office was busily accusing everyone else for the appointment.
From the evidence that wasn’t drawn from gossip, however, Chatham seems to have been Castlereagh’s own choice. Maybe Castlereagh remembered how Chatham had been leapfrogged for the Peninsular command the previous year. Maybe Castlereagh thought that, since the expedition was sure to succeed, a Cabinet member in command could only reflect glory on the rest of the government. Who knows? But on 18 May 1809 Castlereagh wrote the following letter to Chatham, who was ill at the time:
“Private & Confidential
18 May 1809
My Dear Lord
I am anxious to have the great Question on which we conversed yesterday put in a course of proper Investigation. The Admiralty are naturally pressing upon it, and Commodore Owen is come to Town for the purpose of giving his Assistance.
I do not conceive, that any Effectual progress can be made, till we have come to a decision, Who is to be Entrusted with the Execution of the Operation, if it should be determin’d on, nor indeed till this is fixed, can any of the Departamental [sic] Arrangements be satisfactorily proceded [sic] on.
Under these Impressions, and in the hope that the result may prove as honorable to the Commander, as advantageous to the Country, allow me to propose it for your acceptance. In Expressing my own wishes, that it may be confided to you, I am authorized to add the Duke of Portland’s, and I have no doubt those of all our Colleagues.
Until I am possess’d of your Sentiments, I shall not feel myself authoriz’d to mention the Subject to His Majesty, nor indeed can I well take any measures at the Horseguards in furtherance of our purpose.
Believe me my Dear Lord
Very Truly Yours
Chatham’s response to Castlereagh’s offer didn’t exactly burn with enthusiasm:
May 18 1809
My Dear Lord,
I received your letter of this morning, and feel sensibly the kind manner, in which you have proposed to me, the command of the Expedition, now under consideration, and I am much gratified by the concurrence in your sentiments, expressed by the Duke of Portland. Of course, I shou’d be at all times, ready when called upon to obey His Majesty’s Commands, but considering this proposal, as an Option given to me, confidentially on your part, I can only say, that I shou’d be very anxious to have some further conversation with you on this subject, before I venture to give any decided answer to it. I am better, but still confined. I shou’d therefore be happy if you wou’d have the goodness to call here at any time most convenient to you.
My Dear Lord,
Yours Most Truly
Perhaps Chatham already had a premonition of what was to come. If so, I imagine both he and Castlereagh had reason to rue the day he overcame his reluctance and accepted the command of the Walcheren expedition.
 Henry Brougham to Lord Grey, 30 June 1809, from The Life and Times of Henry, Lord Brougham I, 439-40 (London, 1872)
 National Archives Chatham MSS PRO 30/8/366 ff 58-9
 PRONI, Castlereagh MSS D3030/3087