So Downing Street has finally called in the private equity grandees: Hg, CVC, Elliott and friends for a little chat about why they keep giving London the cold shoulder. The answer, frankly, isn't complicated. New York has better liquidity, no stamp duty, and nobody's grandmother asks why you listed there instead.

The reforms are genuinely promising. A stamp duty holiday for new listings, relaxed free-float rules, stock options for directors; these aren't nothing. But when only seven companies have listed in London this year, and takeover bids are outstripping new entrants by 27 to 1, you're not trimming the hedges; you're wrestling a wildfire with a watering can.

The real tell? The LSE has quietly handed Treasury a list of 20 companies  including Shell, Unilever, and, ironically the LSE itself that might decamp to New York. That's not a gentle nudge; that's an ultimatum wrapped in a spreadsheet.

AIM reimagined and lighter-touch listing rules are the right direction. But London needs bold decisions on stamp duty now, not Treasury turf wars and green-shoot press releases.

The watershed is here. The question is whether anyone will actually jump.