There should be no champagne corks popping because the Royal Bank of Scotland has made its first profit in 10 years. For years RBS got drunk on its own hubris. When the financial crisis struck in 2008, its balance sheet – at £2.2 trillion – was bigger than the entire UK economy. RBS ran to Gordon Brown’s government for a bailout. Over two years, RBS borrowed £45bn from the taxpayer. The government still owns 73% of the bank. Big finance’s reckless behaviour left the rest of us with the lowest wage growth in two centuries, record levels of inequality, and the UK’s economy shrunk by hundreds of billions of pounds. RBS certainly partied, but the public have been left with the hangover.

This week Kwasi Kwarteng, Tory aide to the chancellor, accepted that the public were angry over the fact no bankers had gone to prison. He’s right about the sentiment but offered nothing but words. It was Labour’s Jeremy Corbyn who offered an analysis and an answer: that banks were not supporting productive investment but “lending to households and inflating asset prices on a scale never seen before”. Mr Corbyn was right to argue that “deregulated finance has progressively become more powerful. Its dominance over industry, obvious and destructive; its control of politics, pernicious and undemocratic”. Similar ideas, more gently expressed, have been aired by the Bank for International Settlements, which in 2015 said there was a “pressing need to reassess the relationship of finance and real growth in modern economic systems”. Mr Corbyn’s honesty earned him absurd headlines about turning the “City into the last Soviet-era capital west of Pyongyang”.

Britain’s big banks talk a good game about investing in the real economy. However, they have in fact been focused on mortgage lending and consumer credit, engaging in a race to the bottom that is worryingly reminiscent of the years before 2008. Banking’s unproductive energies are one of the destructive legacies of Margaret Thatcher, carried over by New Labour who touted the virtues of “light-touch regulation”. The governments of David Cameron and Theresa May have affected concern over this policy, but have done little about it – so far. True, banks have had to secure extra capital to reduce the risk of taxpayer-funded bailouts. There’s also been a bank levy, which will raise about £1.5bn over five years. The big bang happens in 2019. Then, UK banks with more than £25bn in deposits will have to split retail services from riskier investment divisions. It was John Maynard Keynes who said that “when the capital development of a country becomes a byproduct of the activities of a casino, the job is likely to be ill-done”. The casino is being moved out, but will banks do anything other than gamble on consumer credit and buy-to-let mortgages?

Today’s banks create the cash in circulation and direct where it goes – by deciding who can access credit and who cannot. This gives them the power to determine the level and makeup of investment, demand and production. Labour sees a state-owned RBS as a way to link up technology firms and lenders in a way that is geared towards productive lending. The Tories see state control as inherently bad and plan to sell the state’s holding in RBS – a self-harming act that could cost the taxpayer £26bn. What suggests private banks’ behaviour has changed enough to be trusted again? Massive US fines loom for RBS, and the bank’s disgraceful mistreatment of customers has been revealed. But its CEO still took home £3.5m. If there is a party beholden to an ideology that betrays the national economic interest, it is not Labour.