Imagine that the world economy takes a turn for the worse and slips back into recession. Central banks double down on their quantitative easing programmes. That doesn’t boost growth or bring an end to deflation. They push interest rates deep into negative territory. That doesn’t work either.

At this point, politicians opt for the helicopter money approach. That’s where central banks print money so finance ministries can hand it out to citizens in the hope that they will spend the unexpected windfall.

If this all sounds like the realms of fantasy, think again. Helicopter money is closer than you think. Indeed, the Japanese government is toying with the idea of distributing shopping vouchers to all households, which they could use for child care or other spending.

This is helicopter money in all but name. The vouchers are similar to those distributed by UK supermarkets to customers that accumulate points on their loyalty cards: they expire unless they are used within an allotted period.

The big question is whether vouchers actually work. In a perfect world, the extra consumer spending would kickstart recovery and become self-reinforcing through a pick up in investment. That, however, was not the experience of Japan the last time it tried the idea at the end of the 1990s and, according to Capital Economics, it might not do the trick this time either.

That’s because the Japanese government is planning an increase in sales tax next year, and the likelihood is that consumers will simply spend more in 2016 and then rein back in 2017. The moral for Tokyo is that vouchers will work only if the tax increases are shelved. They probably will be.