If only half of it is spent, it will add nearly 2 per cent to consumer spending.Some commentators have argued that the money - along with maturing Tessas and the interest on them - will not be spent because people treat wealth windfalls differently from income windfalls. There is something in this, but many also regard spending money on consumer durables as different from spending on food or clothes. Not only will they have more freedom over their loans policy, it is putting pounds 16bn (at Mr Mackie's latest estimate) directly into the hands of consumers. Hire purchase restrictions were lifted in the early Sixties, boosting sales of consumer durables. This was when many households got their televisions and vacuum cleaners. The next decade brought the end of direct controls on bank lending.

In the mid-1980s export markets were more subdued but a fall in the pound before Britain joined the exchange rate mechanism improved competitiveness. There is no question but that exports have weakened significantly along with the slowdown in key markets such as Germany But most forecasters expect them to pick up next year. The consensus has export growth rising from 4.5 per cent this year to 5.6 per cent next.On the face of it there is little comparison with the financial deregulation that took place during the earlier episodes. The budget deficit ranged between 1.6 and 5.8 per cent of GDP during the Barber boom, and 1.1 and 2.8 per cent under Mr Lawson, as he then was. Mr Clarke's deficits have run at 5.1 per cent of GDP in 1995 and a probable 4.5 per cent this year and 4 per cent next year.The external environment matters, too World trade grew rapidly in the early 1960s and early 70s. Base rates fell 3 percentage points from their peak in 1962-63, 2.5 points in 1971- 72, 2 points in 1985-86.This time around they have fallen only 1 point from their peak in the preceding 12-18 months.On the other hand, the Government's tax and spending policy is far more relaxed.

Unlike most of the others, they have remembered the rule that the economy is never as well behaved as the forecasts.For proof that booms always come as a surprise, there is no need to look any further back than 1994. In January of that year the consensus forecast was that the economy would expand by 2.5 per cent, driven by consumer spending and investment All agreed it would be a better year than 1993. The common threads are loose monetary and fiscal policy, increasing demand for exports and financial liberalisation Take macro-economic policy first. As it turned out, growth was actually 4.1 per cent.The grandaddy of recent booms took place in 1988, of course. The two brave souls who have predictions of 4 per cent growth and above in 1997 - Tim Congdon at Lombard Street Research and Paul Turnbull at Merrill Lynch - are looking increasingly prescient. The Treasury had one of the highest growth forecasts for the year, at 3 per cent The actual outturn was a 5 per cent leap in GDP. (The fact that the Treasury team had done better than most other economists did little to preserve it from criticism of its forecasting record, just as the fact that the Bank of England's record on forecasting inflation has been slightly better than average is currently not deflecting the myth that it is unduly pessimistic.)Economist David Mackie at City investment bank JP Morgan has compared the 1990s with the Maudling boom in the 1960s, the Barber boom in the 1970s and the Lawson boom in the 1980s.The parallels - hinted at by the charts - make quite a compelling case for suspecting that the Clarke boom is in the making.