Of the remainder, three lost 10% each and 22 produced zilch - though they did at least return their capital intact.

This data has been described as "dynamite" by Eddie Hobbs and "a damning indictment of trackers" by another leading adviser.

A spokesperson for First Active confirmed the "returns quoted are correct". She says markets suffered a downturn "during the period highlighted" but before and after it the bank's trackers did well. "First Active tracker bonds performed in line with comparable products in the industry and customers continued to benefit from the capital guarantee, " she says.

However, Eddie Hobbs was scathing. "Banks took in billions, " the consumer advocate said. "But only now are people realising that all trackers are is a sexed up deposit account with hidden charges [of up to 8pc].

"This confirms suspicions of a wholesale overselling in the market at the time. Some institutions - not First Active - were using back-testing on nominal or highly selective real trackers to fuel advertising to flog these devices.

This is now banned, but too late."

Little AccBank alone made so much money from selling trackers that when it stopped selling on product in 2005, profits more than halved to Euro32.5m.

Recently, the Sunday Tribune revealed that Acc had sold more than Euro650m in bonds in a oneyear selling frenzy. In many cases the bank lent its customers the money to invest. Some weeks after our revelation the bank's chief executive stepped down.

First Active also reaped juicy profits from trackers and encouraged staff to promote them. A confidential document put the "gross contribution" to branch profits alone at 4.3% - a multiple of what deposit accounts would earn for the bank. (Further charges can be deducted elsewhere. ) Sources claimed customers who would normally go for deposits were steered towards trackers, sometimes by staff without extensive training or experience, a charge refuted by the spokesperson. "First Active employees undergo training on all products to ensure we deliver the best possible quality of service to all customers, " she says.

However, our source has evidence that the Financial Ombudsman has ruled against First Active in at least four episodes of misselling investments in recent years. One ruling said the bank "failed to explain properly and fully the nature of the investment".

Another source recounts how staff were "under pressure to sell".

"Staff making a sale of a tracker were often lauded by their manager whereas the opening of an ordinary account with a similar amount was not remarked on at all."