it's so unlike Tim Worstall to get the wrong end of the issue, isn't it?
It's a shame that TW starts off by saying "that is the only part of trickle-down economics that undoubtedly and provably works" and then goes off to attack Zoe Williams instead of dealing with the elephant in the room that the majority of so-called Trickle Down economics *doesn't* work.
Perhaps he could now write an article addressing the principle of Marginal Propensity to Consume, ie why tax breaks (including raising the income tax threshold) mean that the less well-off still spend pretty much all of their income on necessities and maybe the occasional luxury, whilst the more well-off already have enough income to cover their needs, so can afford to save and invest most of the extra money they get, making it grow even more, but taking it out of supply.
The idea is that (like a champagne fountain) you put more in at the top and it trickles down to the bottom. The actual result is that the glass at the top just gets bigger and bigger, so virtually nothing trickles down.
Of course that wouldn't make for a good excuse to bash the lefty Guardian, would it?