> If you buy some shares in M&S or BP on the stock market, the money you pay goes to the previous owner, not the company. You are what Keynes called a ‘functionless investor.’ When such so-called ‘investments’ pay off they extract wealth from the economy without creating anything in return.

Ummm, no: when you pay off the previous owner you reimburse him for the risk he took. What's this guy's solution — not allowing folks to sell their assets? That seems a bit extreme, and liable to destroy the economy utterly.