There are many reasons that fund managers and analysts have provided for the flat performance the British bellwether index over the last 15 years. Not least uncertainty over looming referendums in Scotland and Europe, tumbling oil prices and global recessions, tanking mining stocks or low-performing utilities.

Andy Haldane chief economist, BoE, says a FTSE 100 boss is paid 150 times that of an average worker.

But what about social inequality?

Andy Haldane, chief economist at the Bank of England, said last week that the large and growing gap between the high salaries of FTSE 100 bosses and the average worker is “eroding social capital” – inequality is holding back British growth.

In a speech at Westminster, he said a FTSE 100 boss is paid 150 times that of an average worker.

This gap, Haldane said, “Drive[s] a wedge between management and employees…that in turn erodes social capital.”

The UK’s recovery has struggled since the credit crisis, and has fallen flat since the millennium. The FTSE 100 index is down over 8% in the past 12 months. Between 1 May 2000 and 3 May 2016, the index is down about 1.8%. Despite much hype last spring about the index reaching so-called record highs, a long-term investor has barely seen any growth at all.

That flat performance has of course been replicated by FTSE 100 ETFs. Despite some of these UK equity funds growing to billions of pounds, like the £3.7 billion iShares Core FTSE 100 UCITS ETF (ISF) which came to market in 2000, they would have delivered little value to investors if they had bought into the fund at launch.

An MSCI research report from April 2016 also highlighted the link between large disparities in salary and less profitable companies over time, and found that a wage gap led to lower worker engagement and productivity.

For those investors looking at sector ETFs, it is worth noting that the consumer staples sector had the largest pay gap, according to MSCI, but recent shareholder revolts over large pay packages have occurred across many sectors.

In 2016 alone, there have been shareholder protests at oil giant BP, mining group Anglo-Saxon and engineering company Weir.

More disruption is expected at the upcoming AGM of advertising firm WPP, which wants to pay its chief executive and founder Martin Sorrell £70 million.

ETF investors are already aware of this school of conscious investment, and in recent years ESG and SRI-focused funds have become big business. For example, the £47.8 million UBS ETF MSCI UK IMI Socially Responsible UCITS ETF is up 1.25% in sterling terms year to date – significantly beating the FTSE 100’s negative 1.38% over the same timeframe.

Also watch out for equity ETFs with high dividend yields. Short-termism, Haldane argued, like dishing out excessive amounts of cash to shareholders in the form of dividends, instead of re-investing in the company, is also hurting growth.

Therefore Haldane’s argument is not simply just about the injustice of people earning much more than others – it hurts the economy and investors, too.

But unless the government reforms the 2006 Companies Act to force big businesses to place more weight on their customers and employees, little is likely to change, Haldane said.

(It is worth noting that Haldane himself earns almost £200,000 per year.)