AFTER 2008 I spent a lot of time running about with placards campaigning to put bankers in jail. Last week, though, much to my own surprise, I became a public supporter of a campaign to save a financial whizz-kid sentenced to seven years for major fraud.

In 10 days’ time, Kweku Adoboli, the former trader in question, faces the threat of deportation to Ghana. Kweku, now based in Livingston, came to Britain aged 12 to study at a Quaker boarding school, and has been here for 25 years. He has thus spent his entire adult life in the UK, and, by any reasonable assessment, he poses zero threat to the “national interest”. However, the Home Office automatically review cases with a sentence of more than 12 months, and has decided to threaten to deport him on the absurd basis that Kweku has more links to Ghana than to the UK.

I met Kweku at the STUC’s anti-racism march, and after chatting to him I was immediately drawn to the contradictions in his story. Kweku’s father worked for the United Nations, and his Quaker education instilled in him values of honest hard work and sacrifice for the common good. Yet he became one of the chief fall-guys for the culture of risk-taking that brought down so many global banks. One of the few traders to face any form of punishment for the succession of recent financial scandals, he’s now a convinced critic, a whistleblower if you like, of what he calls the practice of “rentier extractive capitalism”.

A bright young employee of UBS AG, a Swiss global financial services company, Kweku would eventually find himself at the centre of a £1.4 billion fraud, an act that was in part motivated by a kind of Quaker self-sacrifice. His team, he argues, were trying to save UBS from collapse by taking on excessive risks. They were a rookie-type outfit, encouraged and egged on by a reckless management regime. The courts agreed that he had nothing to gain by his actions and accepted he did not personally profit from his deeds, but they nonetheless slapped him with a seven-year sentence. Kweku accepts the decision, although he believes junior traders like himself were scapegoated for the actions of those higher up.

It’s madness to think that, with only 10 months’ experience in the job, Kweku found himself left to run a book of assets the size of the GDP of a small country like Ghana. “It was deeply complex work and no-one else at the bank understood how this book worked,” he told me.

“So, if something went wrong, as we went deeper into the financial crisis, we began to see these dislocations that no-one had ever seen before – it was unprecedented. My job was to find a solution to the losses that we were making, but there weren’t really any rules.”

Essentially, they were inventing rules as they went along, in real time, supervised by senior managers who had no idea how the system worked but were desperate to see it return profits.

The problems were systemic, Kweku argues, and punishing individuals misses the point. He cites the more extreme example of Tom Hayes, a contemporary of his, sentenced to 11 years for fraud in a different department of UBS. Hayes was famously convicted for fixing the Libor rate, one of the greatest scams in financial history. However, Hayes learned his Libor tricks from a handbook produced by higher-ups at UBS. Everyone knew what he was doing, and he was elaborately rewarded for it until the fraud fell apart and he took the fall.

“To make an example, to send some bankers to prison, they went after these young guys,” Kweku says. “But the real problem at the root is the extractive nature of the business. It’s just designed to extract value from the rest of society and, by putting people like Tom Hayes in prison, they are saying, ‘He’s a bad apple, not like the rest of us’. And that’s just not true.”

I don’t doubt that Hayes and even Kweku were jailed for good reasons. “It’s my own fault,” Kweku told me. “I sent an email to take responsibility, and then I was thrown to the wolves. I’ve learned from it.”

However, Kweku’s willingness to work at setting things right is clear. Today he works with colleges, universities, finance executives and the media (he writes for the Financial Times) to make sure Britain learns the lessons from his case. He’s been unsparingly self-critical but, in the process, he’s come to see the flaws in the capitalist system that put him in an impossible position.

Compare the repentance of this junior trader – who worked 18 to 20 hours per day and gained little, and who also came forward to admit his mistakes – with the behaviour of millionaire senior banking executives after the crisis. RBS leaders, for example, remain largely oblivious to the pain they’ve caused and they are totally unrepentant for their actions: you’ll find them living the high life on Edinburgh’s poshest golf courses, largely at taxpayer’s expense. Kweku, by contrast, should be a model for the criminal justice system, a sign that people who cause harm can rehabilitate and become model citizens.

Equally, if the UK Government was seriously willing to go to war with financial fraud and tax evasion, they’d see Kweku as one of Britain’s most valuable national assets. He’s a classic poacher turned gamekeeper. The mistakes he’s made make him an endless source of knowledge and insight into the flaws in global finance. A million training courses could never give his expertise and, as a man of good character, he has learned from a catastrophic mistake.

“I’ve been here [in the UK] for 25 years and I want to use this unique experience to do the right thing now,” he says. “Helping people learn from this gives me a sense of purpose but the Home Office don’t seem to understand this. Is it ‘in the public interest’ for me to do this? Yes, it is, but our current immigration laws are so draconian and unwavering that there’s little room for interpretation – though Parliament has given the Home Secretary the discretion to reverse her decision on a compelling or exceptional basis.”

Kweku’s case is up before the Court of Appeal on Thursday December 7. If he doesn’t succeed, there’s every chance he’ll be unceremoniously dumped from the UK. I believe this would be a major injustice. Kweku is a model for rehabilitation, and a vital asset on the front line against financial fraud, one of the major evils of the world today, and, incidentally, one of the major barriers to the effective functioning of national governments. We should be begging him to stay.

Throwing out this human being, with his vital insights, breaking his relationships and family ties, seems like a violation of any sense of decency, never mind national self-interest. It’s a metaphor for the stinking priorities of a UK Government that’s still in hock to the old corruption of the City of London. If you agree, there’s a petition out there to show your support for Kweku’s case. I’ve signed it and I hope you will too.