In the meantime General La Tour-Maubourg had arrived at Brussels, on August 18, furnished with the draft of a treaty which he was to conclude with the Belgian government for the destruction of the barrier fortresses. In the first instance it was probably intended to keep his mission a secret, but different counsels seem to have prevailed, and, a few days after his departure, Sébastiani informed Granville of the reason of this officer's journey to Brussels. France, he told the British ambassador, claimed the right to negotiate with regard to the fortresses and it was hoped that powers would be given to Sir Robert Adair to act with La Tour-Maubourg in the matter. This request, when in due course Granville transmitted it to London, was refused. Palmerston, in a long interview with Talleyrand, had already declared, in the most uncompromising language, that the pretensions of the French government to have a voice in determining the fate of these fortresses, erected at the expense of Great Britain, Russia, Austria and Prussia, could not be entertained.[151] Immediately on hearing of La Tour-Maubourg's arrival at Brussels Sir Robert Adair, guessing the object of his mission, sought an audience with Leopold. Both to the King and to Meulinäer, the Minister for Foreign Affairs, he asserted emphatically that his government could never admit that the withdrawal of Gérard's troops could be made to depend upon the conclusion of an arrangement between France and Belgium, respecting the fortresses.[152]