Boris Johnson writes today: "[T]he 50p tax is not far, in its political motive, from Stalin's assault on the kulaks."
I'm used to right-wingers trotting out the cliché that Labour wants to "tax the rich until the pips squeak" (never actually said by Denis Healey), but I hadn't anticipated a comparison with the man who pledged to "liquidate the kulaks as a class".
Johnson isn't the first Telegraph columnist to make such an inappropriate comparison. Last week Janet Daley absurdly compared the EU with the Warsaw Pact.
As in the case of its better-known cousin, reductio ad Hitlerum, there should be an informal moratorium on this sort of thing.
Johnson's remarks will delight Tory activists, many of whom loathe the new tax, but they once more put him at odds with David Cameron and George Osborne, who have insisted that everyone must pay their "fair share". Osborne has even defended the 50p rate on the grounds that it will help foster a "more equal society".
This isn't the first time that Johnson has used his Telegraph column to criticise the tax. There is perhaps no other issue on which he writes and speaks with such fervour. Should he continue in his role as unofficial spokesman for the grass-roots campaign against the tax, this could become dangerous for Cameron.
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