 In 1727 he was one of the Corporation's 'Partnership of Five' (with Sir Alexander Grant, William Burroughs, William Squire and John Thomson) who began buying up shares.He and several officers of the Corporation obtained money from it by pawning false pledges, and proceeded to engage in a large scale speculation in the shares of that company and York Buildings Company, also borrowing against the shares purchased so that his partners failed to get what they bought.Robinson obtained a seat in the House of Commons when he was elected MP for Great Marlow in 1731, but was unable to sit before the affair began to come to light.