On the 29th of April, less than three weeks after Nelson left England, but before he joined the fleet, the Cabinet issued orders to St. Vincent to take such measures as he deemed necessary to thwart the projects of the Toulon squadron.  It was left to his judgment whether to go in person with his whole fleet, or to send a detachment of not less than nine or ten ships-of-the-line under a competent flag-officer.  If possible, the government wished him to maintain the blockade of Cadiz as it had been established since the Battle of St. Vincent; but everything was to yield to the necessity of checking the sailing of the Toulon expedition, or of defeating it, if it had already started.  A speedy reinforcement was promised, to supply the places of the ships that might be detached.

Accompanying the public letter was a private one from the First Lord of the Admiralty, reflecting the views and anxieties of the Government.  “The circumstances in which we now find ourselves oblige us to take a measure of a more decided and hazardous complexion than we should otherwise have thought ourselves justified in taking; but when you are apprized that the appearance of a British squadron in the Mediterranean is a condition on which the fate of Europe may at this moment be stated to depend, you will not be surprised that we are disposed to strain every nerve, and incur considerable hazard in effecting it.”  This impressive, almost solemn, statement, of the weighty and anxious character of the intended step, emphasizes the significance of the choice, which the First Lord indicates as that of the Government, of the officer upon whom such a charge is to devolve.  “If you determine to send a detachment into the Mediterranean [instead of going in person with the fleet], I think it almost unnecessary to suggest to you the propriety of putting it under the command of Sir H. Nelson, whose acquaintance with that part of the world, as well as his activity and disposition, seem to qualify him in a peculiar manner for that service.”

In concluding his letter, Earl Spencer summed up the reasons of the Government, and his own sense of the great risk attending the undertaking, for the conduct of which he designated Nelson.  “I am as strongly impressed, as I have no doubt your Lordship will be, with the hazardous nature of the measure which we now have in contemplation; but I cannot at the same time help feeling how much depends upon its success, and how absolutely necessary it is at this time to run some risk, in order, if possible, to bring about a new system of affairs in Europe, which shall save us all from being overrun by the exorbitant power of France.  In this view of the subject, it is impossible not to perceive how much depends on the exertions of the great Continental powers; and, without entering further into what relates more particularly to them, I can venture to assure you that no good will be obtained from them if some such measure as that now in contemplation is not immediately adopted.