There was a brilliant book about the colonisation of Africa, came out a few years ago, The Scramble for Africa.

Colonisation is never good: look at the 1580s and onward in Ireland: English and Scottish 'undertakers' came in, having bought or been granted the property of Irish families, and asset-stripped the land - first the trees, sold and exported to Britain en masse, then any other resources. They stood to their arms for the following centuries; for the occupiers hatred was their survival tactic, for the occupied, corruption became the only way to survive. Not good for a country.

I read an interesting figure a couple of years back: in India, the wealthiest cities (at the time), loaded with gold and pearls and perfumes and spices and silks, were where the East India Company set up, and where the British maintained their centres of power. These are now the poorest cities in India.