The LPU calculated that the total tax and National Insurance paid on these jobs would equal pounds 1,470.56 a year. But if they were replaced by 28 full-time jobs, the Exchequer would receive pounds 41,918.24.The difference between the measures of employment is in part a typical pattern for this stage of the cycle. Company-based measures of employment tend to be higher when employment is falling and individual-based measures are higher when employment is rising. But the graphic shows that the difference is much more dramatic now than in the mid-1980s.The employer-based and individual-based surveys differ most dramatically in construction, transport and agriculture. The extent of temporary and seasonal work in construction and agriculture makes them obvious candidates for 'cash-in-hand' payments; the same is probably also true for tourism.

The difference in measures of employment in transport may be picking up growth in mini-cabbing, a favourite source of black-economy employment.The Federation of Master Builders estimated in June that pounds 12bn of undeclared work would be carried out in its industry this year. This is one area of the black economy to which the Inland Revenue has been paying particularly close attention. Others include auditors, insurance agents, scrap dealers, car salesmen and guest- house proprietors.Leo Doyle, an economist at Kleinwort Benson, believes that the employment figures generated by the individual-based survey imply growth in consumer spending half a percentage point higher next year than calculations based on the more subdued survey of companies. He argues that spending may have been boosted by hidden incomes rather than a falling propensity to save. Personal saving as a proportion of income may have stayed at recession levels. This would be consistent with reported rises in consumer confidence.Growth in undeclared incomes might also help to explain why growth in high-street spending volume continued to accelerate last year, even when growth in household incomes (after taking account of inflation) began to fall.Mr Doyle's conclusions are corroborated by evidence that more transactions in the economy are being carried out with cash rather than via cheque or credit cards. Apacs, an umbrella group for banks and building societies, was astonished to find that the number of hard cash transactions rose by 200 million to an estimated 16.8 billion in 1993, after years of decline.

Link, the country's largest cash machine network, said last week that withdrawals in July reached a record 15 million. This figure was up 14 per cent on a year ago and surpassed withdrawals last Christmas.Gross domestic product figures paint a similar picture. By definition, everything that is spent on goods and services should become someone's income, in the form of wages, profits or rent. But the Central Statistical Office's measure of national spending was 4.8 per cent higher in the second quarter than a year earlier, while growth in national income was less than 4 per cent.