Like many of my compatriots, I listen every morning to the Today programme on BBC Radio 4. This morning there was a fascinating discussion (it’s at around 134 minutes here) between one of the presenters, John Humphrys, right-wing Conservative MP John Redwood and the head of the Institute for Fiscal Studies, Paul Johnson. The subject of the discussion was the current maximum 50 p income tax rate. Johnson explained that even before the government increased the rate to 50 p, the top 1% of income tax payers (those earning over ¬£ 150,000 a year) had been paying 30 % of all income tax. The Treasury, in other words, was highly dependent upon them. Half of that 30 % came from the just 40,000 people who were earning over ¬£ 500,000 a year. These were precisely the people with the means to seek expert advice on how to reduce liability and/or move elsewhere. It was hard to know what effect the 50 p rate had had but when the rate had been at 40 p the government had got more revenue from the top 1 % than when it had been at 60 p (in the 1980s) or 90 p (in the 1970s). John Humphrys had clearly expected an ideological approach from John Redwood and was just as clearly disappointed. Redwood was solidly pragmatic. The government needed to maximise revenue and therefore it had to make sure that top taxpayers ‘stayed and paid’. Johnson added that, though it was difficult to tell and there were no statistics yet, the 50 p rate seemed to be a bit above the revenue maximising rate and had a sort of psychological significance. And it was recalled that as a shrewd Chancellor¬†Gordon Brown had always kept it to 40 p…