“This has reinforced the principle behind ‘passive’ investing that big is beautiful, punishing fund managers and their investors who take dissenting view with their portfolios,” Mr Khalaf said.

The global sector has been hard to beat for the same reason. The US stock market has grown to such an extent that it now accounts for two-thirds of the global stocks benchmark. “Global tracker funds therefore increasingly resemble US tracker funds making it more difficult for fund managers to compete,” Mr Khalaf added.

Alan Miller, of wealth manager SCM Direct, said the higher charges and trading costs were also a drag on returns and another factor behind why stockpickers were falling behind their tracker fund rivals. He said: “Passive investors benefit from lower costs, greater diversification and much less risk of choosing the ‘wrong’ fund that fails miserably. Its no wonder investors are voting with their feet,” he said.

However, it was not all grim reading for active investors. Those using funds for British stocks fared better, with two in five managers beating a passive rival. The domestic market has proved a relatively fertile hunting ground for stockpickers as it has not been as well researched as the US, leaving scope for managers to find hidden gems.

It also has a larger composition of smaller companies which historically offered higher returns, according to AJ Bell.  

While this year has been particularly poor for active fund managers, the chances of a DIY investor picking a market-beating fund is improved when looking over longer periods. Half of managers beat their benchmark index over five years while 56pc did so over 10 years.