"In November of 1770, the [British] Board of Trade advised the King and his Council to disallow Virginia's act imposing an additional duty on imported slaves...According to the Board of Trade, Virginia's assembly intended to prohibit absolutely the slave trade. Such an action, in the board's opinion, would damage the economy of Great Britain and the colony. The lack of new slaves necessarily would limit tobacco production and would in turn raise prices, reduce consumption, and ultimately diminish the Crown's revenue from the tobacco trade...The Privy Council accepted the board's recommendation..."[A Planters' Republic, 1996, citing Board of Trade to His Majesty, 23 Nov. 1770]
"...the burgesses requested that the King 'remove all Restraints on your Majesty's Governors of this Colony, which inhibit their assenting to such laws as might check so very pernicious a Commerce.' " [A Planters' Republic, 1996, citing Journals of the House of Burgesses, 1770-1772]
These requests by the Virginia House of Burgesses can be found in other sources too.
Very interesting links!