Re: You're all smart people (cough cough)
I also earn income in India, or my company does. Our clients withhold tax on the revenue, which due to a double taxation agreement between India and the UK is then offset against UK corporation tax. Specifically, I get a form from the buyer and supply it to my accountants who factor it all in to the UK tax calculations. This happens with several countries, it's not uncommon. And I won't say it happens consistently - some Indian customers do this, others don't. So I think it's fair to say "it varies".