Two events this week three thousand miles apart. In New York, Barclays paid $4 million (£2.5 million) for naming rights to a subway station. In future, Atlantic Avenue-Pacific Street, a teeming commuter station in Brooklyn, will have the word Barclays added to its already clumsy moniker.

In London, Alistair Darling renamed the discredited Tripartite Committee, calling it the Council for Financial Stability, the centrepiece of his plans to beef up financial regulation and so try to prevent a repeat of the banking crisis.

Two very different renamings, but they are not entirely unconnected.

Barclays has grand ambitions in high-risk investment banking, wanting to displace Goldman Sachs as the pre-eminent player in the world. Having snapped up the near-dead Lehman Brothers and breathed new life into it, the bank is intent on building the Barclays brand in America, where it is little known, and is disgorging big bucks to do so.

Sponsored place names are one of the most spirit-sapping innovations of the 21st century. (How long before Tube travellers find themselves strap-hanging from Elephant & Virgin to Coke-fosters by way of Piccadilly Nike?) But the practice does at least fill civic coffers. And for Barclays, it is one way of embedding the bank’s name in the consciousness of New Yorkers.

Mr Darling, meanwhile, wants to persuade us that he is doing more than tinkering round the edges of bank regulation. Renaming the committee of grandees from the Treasury, Bank of England and Financial Services Authority may be no more effective than replacing Windscale with Sellafield, but one can argue it symbolises the will to change.

Many of Mr Darling’s proposals are sensible. Forcing banks to hold more capital and liquidity; putting pressure on bank boards to reform bonus structures; trying to inject counter-cycles into the system so that capital cushions are built up in the good times; getting regulators to focus on dangerous, herd-like trends rather than just on individual banks; forcing the industry to build the depositor lifeboat in advance of bank shipwrecks rather than after the event — these are all laudable aims.

But the central question of whether taxpayers should continue to underwrite the adventures of ambitious investment bankers is ducked. Mr Darling rejects the complete separation of investment banking, or casino banking as it has been dubbed, from conventional commercial banking. We are told that somehow his proposed reforms will insulate depositors — and in extremis taxpayers — from catastrophic losses by investment banks, but not quite how.

Barclays is surely the perfect test of this. From a safe distance, Britain might applaud the imperial ambition of Bob Diamond, the Barclays No 2 who runs investment banking. But there seems absolutely no reason why British taxpayers should implicitly underwrite his grandiose and high-risk plans.

The test for Mr Darling’s new regime is simple. If the investment banking arm of Barclays were to be ruined by a rogue trader or brought down by a “fat finger trade” or scuttled by a strategic blunder like the ill-fated rush into credit securitisation, what safeguards are in place to ensure the devastation does not reach either ordinary depositors or UK taxpayers?

The last word has not been spoken on bank regulation. So far, taxpayers are on the hook for £1,260 billion through loans, guarantees and capital injections into the banks. That’s equivalent to Britain’s entire output for 11 months. The Chancellor reckons the actual cost will be no more than £50 billion — still a colossal sum but manageable, equivalent to a penny on income tax for 14 years.

Similarly, the cost in terms of slower economic growth, job losses and business failures is for now unknowable. A nasty recession for 18 months followed by a return to trend growth is one thing; a ten or 15-year phase of abnormally low or no growth would be quite another.

Until we know the true cost of the current crisis, it is impossible to say how draconian a crackdown is needed, or wanted by the public.

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