Financial Conduct Authority (FCA) chief executive Martin Wheatley has called on firms to do more to support vulnerable customers, saying their mistakes made difficult situations worse "too many times".
Wheatley (pictured) said he did not expect firms to perform "a wholesale redrawing" of their processes and systems or for their customer-facing staff "to become social workers".
But he expects firms to "allow staff to treat customers as they would like a member of their own family to be treated", he said.
The regulator published a paper on treating vulnerable consumers in February, designed to encourage debate among academics, practitioners and policymakers.
The paper found "problems at every stage" in the way firms deal with vulnerable consumers, including poor communication and poor training of frontline staff.
Wheatley said the FCA wants firms to be flexible and adapt their processes when sticking to strict instructions risks creating bad results for those in vulnerable circumstances.
He said the FCA recently worked with the financial Ombudsman on preventing complaints about power of attorney and concluded "too many times" misunderstandings and mistakes made by firms "contributed to exacerbating the situation".
He wrote in the Financial Ombudsman Service's latest newsletter: "Our industry has come under significant pressure in the last few years to rediscover its sense of social purpose.
"We believe that vulnerability is an issue that should be at the centre of that debate - and it's clear that this is becoming an increasingly significant issue for consumers too.
"The moral case for supporting vulnerable customers is clear but so is the business case.
"Firms have legal responsibilities and a duty under our rules to ensure customers are treated fairly. More than that, firms should ask themselves what loyalty they can expect from a customer - or their family - given poor service in their hour of need."
Software provider Suitable Strategies said the regulator's definition of who is vulnerable does not go far enough and has to include those with gaps in their understanding of financial terms and products - about half the UK by its estimate.