A reverend, a tiler, an academic, an environmental campaigner and a former investment banker are trading verbal blows in a bright, modern church hall in south London in December.

What's really getting the debaters worked up as they face each other from opposite pews, overlooked by figurines of angels, is the topic of ethics in the banking industry. One point they all agree on - there isn't enough of it.

The problem - and the source of contention - is what to do about it.

So if bankers all just start acting like good chaps, everything is going to be ok? asks one skeptic, to loud applause.

Sparked by the recent wave of anti-capitalist movements, manifested in Britain by Occupy London protesters camped out by St Paul's cathedral, it's a gathering that would have been hard to imagine a year ago, when the evening's most high profile speaker, Ken Costa, was still chairman of the international branch of investment bank Lazard.

While bankers' bonuses and regulation have been burning issues since the 2008 financial crisis, until now there have been few signs of a real willingness in the industry to engage with an outraged public and seriously discuss reforms.

Discussions like the one in Lambeth's Oasis Church, set up by its minister Steve Chalke and Occupy London, are one sign of an evolving view, in part brokered by a Church of England that was thrust into the mix by the protesters' presence at St Paul's, which is adjacent to the London Stock Exchange.

Banking groups in Britain are also for the first time exploring options of their own, like the creation of professional standards enshrining some of the unspoken rules and traditions that were the hallmarks of the old City of London.

TALES OF GREED

No matter what happens to the two-month old Occupy movement at St Paul's, it will have succeeded in bringing to the surface an anxiety pervading even in some banking circles for some time.

Over the last 10-20 years a sense of duty, obligation and responsibility has been supplanted by the cult of the individual and individual greed, said Bobby St John, a managing director in Royal Bank of Scotland's corporate and institutional banking business.

Managers across the banking industry were saying 'we need to keep the machine rolling, we need to keep generating larger profits' and individuals were incentivized to take bigger and often irresponsible risks.

St John, like former Lazard banker Costa, is a practicing Christian, and he points to the strong religious principles that many City institutions, like the livery companies or trade bodies, were originally built on as a contrast to today's financial world.

You don't have to be an adherent of Christian values to be concerned, however.

Recent tales of products being improperly sold have shocked some in the industry - whether it's investment banks like Goldman Sachs and Deutsche Bank criticized by U.S. senators this year for the way they handled subprime mortgage products during the crisis, or retail scandals like the one at HSBC, fined for ripping off elderly clients.

The push by some bankers to bring ethics back into the industry owes a lot to a hankering for a bygone age, before the deregulation of the mid-1980s known as Big Bang, that saw small traditional partnerships disappear.

Individual honor and responsibility - encapsulated by the mantra my word is my bond - were a pillar of this old-fashioned City, which some now hope to recapture.

U.S. investment banking powerhouse JPMorgan took its motto -- first-class business in a first-class way -- from its namesake John Pierpont Morgan, who warned in a 1933 speech that a disregard of ethical codes would cost bankers their reputation in the community.

SOFTLY AND SUBTLY

Sweeping structural change since these times will be tough to reverse, however. The Big Bang propelled Britain into the era of universal banks, where all kinds of businesses, including retail and investment banking, could sit side by side.

This meant you could suddenly have multiple businesses under one roof that were previously separate. Before you had real Chinese walls, said Philippa Foster Back, director of the Institute of Business Ethics, a group created just after Big Bang.

So they (IBE founders) had a big concern about potential conflicts of interest.

One path advocated by Costa, who was brought in by the Church of England to mediate with the Occupy London protesters, is an appeal to hearts and minds, along with effective regulation.

The 62-year-old, a warden at evangelical church Holy Trinity Brompton known for his rousing addresses to the congregation, proposes combining the unwritten laws of conduct, which he defines as the softer, subtler, cultural values of honor, honesty, integrity and decency.

For some, it's a vision that lacks substance.

In a show of hands over whether the ills of capitalism and banking can be fixed by simply emphasizing ethics more, only a third of the 200 people gathered at the Oasis Church that December evening - a mix of Occupy protesters, interested students, retired economists and church-goers - agreed.

And within the industry, many are still skeptical.

Ethics? I don't even know how to spell that, scoffed one senior equities banker at a major firm.

Major challenges in convincing the wider public that there can be ethics in finance will include overcoming the deep mistrust of the banking industry that has come out of the crisis and dispelling doubts over its value in society.

Banks are slowly realizing that it's an image problem that cannot be ignored.

Barclays boss Bob Diamond - slammed by politicians in the past - made a rare bid last month, in a radio lecture, to explain how businesses as diverse as an ice cream firm, a surgical blade maker and a car parts supplier thrive on banks' services.

SHIFTING MIND-SETS

Some attempts have also already been made to crystallize the approach promoted by the likes of Costa in a formal code of conduct.

The Chartered Banker Professional Standards Board, an initiative launched only in October this year and backed by senior executives from Santander UK, HSBC and Virgin Money among others, drew up such a code at inception.

As well as underlying issues of risk and compliance, the list of seven goals urge bankers to act at all times, in a fair, honest, trustworthy and diligent manner.

The group now aims to develop a series of professional standards to support the ethical awareness and ... competence of those working in the banking industry by next December.

Lobby group TheCityUK has also been working on an initiative to tackle, among other problems, the breakdown in trust between society at large and the financial services industry.

Their Next Generation Vision, conceived by young financial sector workers after a series of study groups, also champions the idea of a formalized moral code.

They are also concerned about how to convince people outside the industry that attitudes are changing.

Coming up with those things inside the City, and then feeling like we can pat ourselves on the back and say great, we've got a moral code ... that's internalizing the issue, said Adrian Frost, 37, a banker in the corporate advisory team at BNP Paribas who took part in the Next Generation Vision program.

Financial education, even at a lower school level, is one way forward the program is keen to promote.

For now, the consolation for those in banking who want to see a genuine shake-up of ethical standards is that they are convinced mind-sets are gradually changing within the sector, at least.

St John at RBS said more companies and banks have been putting out mission statements since the crisis about treating people fairly and behaving with integrity.

The mission statements have been looked at in a fresh way, whereas before it might have been in some dusty document sitting on a shelf, he said.

(Additional reporting by Laurence Fletcher and Jane Merriman; Editing by Sonya Hepinstall)