Despite moves by banks to change their culture and become more customer-focused, Which? said its findings suggest that the reputation of the industry has slumped further in recent months, with fewer people thinking that bankers act ethically now than they did even in the wake of the Libor scandal.
Nine out of 10 Britons would trust the scandal-hit banking industry more if bad bankers were struck off, a consumer group has found.
Just one in 16 (6%) people it surveyed believe that bankers act in their best interests - down from one in 11 (9%) when research was carried out last summer, soon after the Libor rate rigging scandal broke.
As the Parliamentary Commission into Banking Standards prepares its final report into the industry, 93% of more than 2,000 people surveyed across Britain by Which? said that their trust in the industry would be increased if bankers were struck off for wrongdoing. Three-fifths of people thought it was unlikely that a banker would lose their job if they lied or cheated.
The commission was set up to look at standards and the culture of banks and to make recommendations for action.
British Bankers' Association (BBA) chief executive Anthony Browne said the industry's "number one priority" is to restore trust and confidence in the banking sector.
He said: "This survey confirms just how poorly bankers are held in the public's esteem right now and the scale of the challenges facing the industry. We understand why people are angry, which is why the banking industry is embarking on an unprecedented programme of change."
Which? wants to see bankers forced to comply with an independent code of conduct in a similar way to doctors and lawyers. Some 86% of people it surveyed agree that a banking code of conduct should be compulsory and 78% said consumers should have an input into these rules.
The group's executive director, Richard Lloyd, said: "It's damning that fewer consumers think bankers act ethically now than they did immediately after last summer's Libor rate rigging scandal, when we thought the reputation of banking had hit rock bottom.
"But since then we have continued to see senior bankers criticised for catastrophic failures, and not doing enough to turn around poor standards of basic customer service."