Calculating Britain's Debt to India

In the 1870's Dadabhai Naoroji, later twice President of the Indian National Congress, estimated that Britain was bleeding India at the rate of three to four million pounds per year. Or was it thirty to forty million? I need to check on that. Anyway let's stick with the lesser amounts for now. Average those to 3.5 million pounds per year. Assume that that sum was constant from 1857 to 1947. Assume further that the British looted a paltry 1 million pounds per annum from 1767 to 1856. Assume a 7.875% rate of annual interest compounded yearly. That must be a good rate because that is what I'm paying through the initial years on the adjustable-rate mortgage on my house. Then we calculate

Sum_{n = 1997 - 1767}^{n = 1997 - 1856} (1.07875)^n +
3.5 * Sum_{n = 1997 - 1857}^{n = 1997 - 1947} (1.07875)^n = (0.07875)^(-1) [(1.07875^231 - 1.07875^141)
- 3.5 * (1.07875^141 - 1.07875^50)] million pounds.
That works out to about 521,000,000,000,000 pounds, to be divided between India, Pakistan, and Bangladesh. Interest is currently accruing at the very serious rate of 41,000,000,000,000 pounds per annum. I haven't included damages, and interest thereon, for the Bengal famine, the Jallianwallah Bagh, and other like injuries. I haven't even included "gifts" like the Koh-i-noor. How much must we Indians have loved George V (or was it Billy XVII? Saala mammary no work today.) to have given him a nice gift like that to stick with glue on his gold crown! And where he stole gold and glue?

http://www.kahany.com/writing/0997britishdebt.html