In the Netherlands Falck was called the king's 'good genius', but William I tired of his counsels and he was superseded by Van Maanen. He was an ambassador in London when the disturbances of 1830 convinced him of the necessity of the separation of Belgium from the Netherlands. He consequently resigned from his post and lived in close retirement until 1839, when he became the first Dutch minister at the Belgian court. He died at Brussels on 16 March 1843. Besides some historical works he left a correspondence of considerable political interest.