 As envoy, Harris immersed himself in Dutch politics from 1784 on and managed to become the "de facto" leader of the Orangist party.He and his French counterpart, Charles Olivier de Saint-Georges de Vérac, the French ambassador to the States General of the Netherlands, fought a secret war with the help of agents of influence, like the then-Grand Pensionary of the province of Zeeland, Laurens Pieter van de Spiegel, and the confidential agent Hendrik August van Kinckel, and spies like Pierre Auguste Brahain Ducange.Harris returned to London in secret at the end of May 1787, where he managed to convince the Cabinet to endorse a policy of subversion in the Dutch Republic, to be funded by £70,000 from a slush fund, laundered through the king's Civil list.