It is basically a copy of the British New Land Pattern cavalry pistol, widely used by the British East India Company and thus widespread in the India/Pakistan/Afghanistan region.
Due to the rather crude workmanship and lack of markings, I believe it is was locally made, not made in England, but it is well enough made that it was, IMHO, made as a weapon and not as a tourist souvenir as many guns have been in that area. Even today, native craftsmen in that region manufacture "old" guns to sell to American soldiers (who are banned from bringing back most modern arms), and that could be one of those, though I don't think so. It would, if I am correct, date to the early 1800's and cleaned up and checked over by a gunsmith, could probably be fired.
Jim
