A couple of years ago, when structured investment vehicles were sowing devastation in the financial world, I frantically searched for a way to explain to non-financiers how these entities worked. The analogy I resorted to was a garage or cellar.

For just as a garage or cellar is usually attached to a house – but not truly inside a house – entities such as SIVs and conduits have traditionally had a semi-detached status with banks. That served the banks dangerously well in the years of the credit boom, since they used SIVs as a place to store irritating stuff which they did not want cluttering up their balance sheet – such as a household stuffing rubbish into a cellar, so that it does not mess up the smart front room.

These days, of course, the word “SIV” has become almost as taboo as the phrase “subprime securitisation”. Yet, as I perused this week's announcement that Barclays plans to sell $12.3bn of credit assets to a “newly established fund” called Protium Finance – which will be independent but mostly financed by a loan from Barclays – it was hard to escape a twinge of déjà vu.

To be sure, the details of the Barclays plan differ in some crucial ways from the old SIVs-cum-cellars. One central sin that bedevilled the SIVs was that banks often used them for regulatory arbitrage. Another was a reliance on cheap, short-term financing – which disappeared, with disastrous consequences, when the crisis started in 2007.

However, as Barclays repeatedly stressed this week, Protium is not focused on regulatory arbitrage: those $12.3bn assets will stay on Barclays' balance sheet for regulatory purposes, in the sense that the bank will be forced to make big capital provisions against a $12.6bn loan it is extending to Protium. Moreover, Protium is not exposed to the funding risk that blew up the SIVs, thanks to that monster loan.

But in another sense, there is an uneasy echo of the past. Most notably, by selling those $12.3bn assets to Protium, what Barclays is essentially doing is taking a pile of toxic items out of its front room (ie the balance sheet) and stuffing it into an entity that is not inside the house (the garage, or cellar).

After all, the fine print of the Barclays announcement makes it clear that while the British bank is going to count the Protium assets as being “on balance sheet” for regulatory purposes, it is removing the assets from the balance sheet in accounting terms, since Protium is legally “independent”, based in the Cayman Islands.

That means the bank will not need to report the mark-to-market value of those assets, or reveal the source of equity finance for Protium that supplements the Barclays loan. Nor will it need to control the pay of the people running Protium, since they do not count as Barclays staff.

Now, many bankers would argue that such ring-fencing is not just sensible, but inevitable in the current world. Putting these assets into a dedicated unit, after all, puts them under the control of an experienced management team.

It also makes the “front room” of Barclays look smarter, since it shields the main balance sheet from sudden fluctuations in the value of toxic assets – and clarifies for shareholders where those assets are. In many ways, that represents progress. After all, at many western banks it is still a mystery what is (or is not) happening to all those troubled credits, or who is (or is not) sorting them out.