Udny became an
indigo planter in the
Bengal Presidency, in the role of Commercial Resident. Initially, in the 1780s, he was the main assistant to
Charles Grant in his silk factory near
Malda city. It was at English Bazaar (
Ingraj Bazar), in the fortified compound of the Commercial Resident. Grant also was an indigo planter in the area, in business on his own account. This he claimed as an innovation, at Gaumalti (near
Gauḍa south of Malda), and he stated the intention of developing alternative employment for local weavers. The commercial viability of the crop, as a
commodity used for
dying, turned out to be problematic. Udny succeeded Grant, who moved to Calcutta to head the Board of Trade. He took up the position of Commercial Resident in 1787, holding it to 1799. From 1788, Grant supported indigo planters, in particular with loans. The Baptist missionaries John Thomas and William Carey arrived together in Bengal in November 1793, and were soon in financial straits. Thomas was a naval surgeon and a protégé of Grant, a noted
evangelical, who brought him to Gaumalti to carry out mission work in 1787–9. He had more recently been in Malda studying
Bengali. Thomas therefore knew Udny well, but they had not parted on good terms, Udny withdrawing support because of erratic behaviour by Thomas. When Udny's brother Robert and wife Ann died in a boat accident, Thomas made it a pretext to contact Udny. There resulted an offer from Udny, of salaried managerial employment at new indigo factories being set up by Udny in the Malda area, north of the city and towards
Dinajpur. At the time the early effects of the
Haitian Revolution of 1791 had removed supplies of indigo from
Saint-Domingue in the European market. In 1795, the East India Company put heavy funding behind the crop, because of its place in
remittances for its British employees. A few years later, however, Great Britain was experiencing a
glut of Indian indigo. For Thomas this factory post was at Moypaldiggy (Mahipaladighi, "the tank (reservoir) of
Mahipala I",
Bansihari). He continued to let down his patrons, left the indigo factor role to trade in sugar, returned, and died in Dinajpur in 1801 of infectious disease. Carey was in charge of the factory for five years, studied the languages of Bengal, and left to join
William Ward and other missionaries in
Frederiknagore, Danish territory where their work was allowed. ==In Calcutta==