Rachel Reeves's most irritating manifesto fudge was on the tax loophole for private equity

It has been almost two decades since Nicholas Ferguson, a grand figure in the private equity business, caused a storm by talking out loud about his industry's dirty little secret.

- Nils Pratley

It could not be right, he said, that highly remunerated private equity executives could pay less tax than low-paid workers.

Things have moved on a bit since 2007. So-called "carried interest", or carry - the portion of an investment profit that the private equity managers retain as a bonus for success - is now taxed at 28% under the capital gains regime; in the old days, rates in effect as low as 10% could be secured thanks to various exceptions.

But the underlying point remains. Why on earth should a performance-related bonus be treated as a capital gain rather than as income, where it would normally be taxed at the higher rate of 45%? Bonuses in banking and other parts of the financial sector don't get the same special treatment.