Coming Soon? A Robin Hood for our time

$1.9 trillion is traded daily on the London markets - a huge proportion of the trading serves absolutely no useful economic purpose. Much of it is economically harmful: worse still the trades carry huge social costs, largely imposed on poor people. This blogger has worked on currency hedges and knows all too well how vulnerable weak economies are to predatory attacks by traders backed by massive offshore funds.

Economist James Tobin originally conceived of a tax that would throw sand in the wheels of these trades. This idea has been developed further and there are now many different types of transaction taxes on financial trades. And the idea has spread from the margins to the core of international debate.

BBC's Newsnight programme has explored the issue at length. Watch it here.