In nominal terms, US equities made no money between 1998 and last year, with negative annualised returns of -0.3 per cent. Only those rolling ten-year periods ending in the Great Depression years of 1937, 1938 and 1939 did worse, the study showed. In the UK equity market, the past 10 years delivered a total return of just 1.05 per cent; only the decade ending in 1974 did worse, at 1.0 per cent.

The slump in global market indices last year, coupled with heavy losses in most other asset classes, have encouraged wealth managers to advocate shifting into cash, high-grade government bonds and gold.

Barclays Capital warned, however, that disillusion with equity returns, while understandable, carried risks if investors choose to spurn this asset class.

“Prospective returns from equities are the most attractive levels seen for some 20 years in the US and 25 years in Europe and the UK,” the report said.

The weak returns seen during the past 10 years are not caused by some intrinsic problem with equities as an asset class but are a consequence of the extreme over-valuation.

The track record of equities looks far better over a much longer time period.

Since 1899, equities have clocked up real returns of 4.9 per cent, while gilts – typically seen as a less risky asset class – delivered real returns – after inflation – of just 1.2 per cent. As far as cash is concerned, returns over that 109-year period were only 1 per cent.