Sue Lewis: 'My parents kept their money in a jam jar'

There's something I can't get my head around after meeting Sue Lewis. Both of her daughters, born after 1982, are "millennials", with all the unwelcome economic baggage that this brings, and yet only one of them comes to her for financial advice. The other – get this – "likes to talk to her bank".

Our austere first-floor meeting room in Canary Wharf's Financial Conduct Authority (FCA) resonates with laughter. This, you see, is deeply ironic given her mother's latest role: chairing the City watchdog's consumer panel, which – and you'll have to trust me on this – is livelier than it sounds.

It is especially incongruous given Lewis's deep antipathy towards banks, which you would think might have rubbed off on her children. It's a theme that Lewis, whose job as the UK's newest consumer champion is to pick fights with the financial services industry, returns to repeatedly during our interview, and it can be boiled down thus: "Banks aren't at all interested in consumers."

Lewis, 60, a career civil servant, learnt this when she worked on Don Cruickshank's 2000 review of the banking sector, which blasted banks for overcharging customers by up to £5bn a year. This was mere peanuts set against the £65bn and more that the bailout has cost UK taxpayers, perhaps, but it started Lewis thinking. Working for the Treasury on investment and savings policy and "seeing who came and knocked on the door of the Chancellor, [and] who got a hearing" – namely the aforementioned banking industry – only stiffened her resolve to even things up.

She wants to improve everyone's financial lives, which, sadly, doesn't mean writing out fat cheques, but does mean recognising that "there are a whole bunch of consumers out there, not just middle-class men". The last bit is a direct jibe at the FCA's discredited predecessor, the Financial Services Authority, which was disbanded for failing to do its job and prevent the economic abyss into which we all fell after Northern Rock collapsed.

Banks, Lewis says, "just didn't get punished hard enough for taking the country to the brink". Worse yet: "They still have no shame about it. There's a large part of the banking industry that is going, 'Yeah, it's just business as usual.' They owe the country. They owe you and me and every other taxpayer for bailing them out. They really ought to be giving something back, and that makes me quite cross."

She has a long list of things she would like the banks to change, starting with "talking to consumers in a language that they understand". This, along with a pledge to tackle "cross-subsidies – the bad ones, between poorer people and rich people", will dominate the consumer panel's to-do list, when it meets to set its priorities next week. "Warning systems" to stop people going overdrawn, such as texts that alert you when your balance is below £50 and you have a direct debit due, would be easy to implement, she points out, puffing on her e-cig.

"The whole way that banks incentivise is not very pro-consumer, because they make their money out of hidden things, mistakes such as an accidental overdraft or a direct debit not being paid. It advantages those who can afford to be in credit all the time and don't make mistakes at the expense of, well, my children, who don't have very much money and so tend to slip into overdraft."

If you're wondering, the daughter who does come to her mother for advice is the younger one. "She'll ring me up and say: 'Here's five insurance policies. What do you think?'" With good reason, as it turns out: the cheapest travel insurance, which the 26-year-old in question was poised to take out "didn't cover any respiratory illness. So if she got a chest infection – she's going to live in Burma for a while – she wouldn't be covered, which seemed completely weird."

It's anomalies like these that make shopping around such a hassle for all but the über astute, Lewis says. "It's those day-to-day irritations that lose the trust" between consumers and financial institutions. "It's not that you couldn't make a good decision if you sat down and thought about it, but it would take you an hour and you'd probably rather be doing something else. And even after that, you couldn't be sure that something you wanted was covered."

Lewis, who lives in Brentford, north-west London, and works two- and-a-half days a week as a consumer champion, says she qualifies to stand up for the cash-strapped because "my own background is struggling on very little money". This meant growing up in a council flat just outside Watford, with a dad who worked in a factory and a mum earning "pin money". Her parents had a simple approach to their finances, keeping their cash in a jam jar rather than a bank account.

A previous job, as finance director for Sure Start, the Labour-backed children's centre project to support families with kids under five, gave her another window into the lives of people "struggling on very little money". Here she can't resist showing her feisty side, straying "off piste", much to her FCA minder's disapproval, and taking a pop at the "great scandal" of Sure Start – the middle-class takeover that all but killed the scheme, which was established to reduce the stigma of being poor and needing help.

"Anyone could use it so, of course, all the ministers' mates came along and said: 'Oh, we like the look of this. Can we have one in Chelsea?' Which just completely defeated the object of having that extra bit of care for the very young children of parents who, for whatever reason, couldn't work their way through the system, which middle-class people can do."

I'm curious about Lewis's own financial affairs, which I imagine must positively sparkle. But no – inertia afflicts her as much as the rest of us, it turns out. "There are things I can't be bothered to do," she admits.

The trick is to try to stop banks profiting from that apathy. It looks as if Lewis's daughter won't be the only one seeking a chat with the bank – sorry, make that banks.