Over 3,000 export licenses for the sale of arms and other military equipment to states on the Foreign Office's countries of human rights concern have been issued, MPs have found.
The combined value of the licenses, which remain in force, came to more than £12 billion, according to the Commons Committees on Arms Export Controls (CAEC).
Iran, Sri Lanka, Saudi Arabia, Russia, China and Belarus are among the countries who have been issued licenses.
There are only two nations out of the 27 on the Foreign Office's list of concern that do not hold valid licenses - North Korea and South Sudan.
The CAEC said the numbers were "surprisingly large" but acknowledged many of the licences were for dual-use items (military or civilian).