Thalasseri or Tellicherry in the late 18th century was a harbour-fort which was held by the British East India Company as a factory. The value of Tellicherry as a naval base meant that her capture could seriously impact the British naval situation on the west coast. Also rebels in North Malabar bought arms and ammunition from the British in Tellicherry. So if Hyder could capture this fort, he could, at a stroke, cripple both the rebels in North Malabar as well as the British military power at a regional basis.