In their view, people think of a large lump-sum tax cut as new wealth and thus save it, while they think of the extra money that shows up in their weekly paycheck as additional income and spend it.
Prof Miles says the easiest way to think about a "helicopter drop" is as a lumpsum temporary tax cut - or a one-off reverse poll tax - financed by new government bonds which are purchased by the Bank of England on the secondary market, but with all interest and redemption payments etc transferred back to the Treasury.