This could be the ultimate 'green shoots' story. As we all try to get out of debt, I can now tell you that I have, after six months, finally repaid my Nectar loyalty points overdraft.

Eh? Here's what happened. Last Christmas, Mrs Shareholdervalues was doing all the festive food shopping at Sainsbury's. I arrived a bit later and started getting in all the festive booze. Mrs Shareholdervalues was loading up her shopping and paying at one till, while the master of the house was going through another till with all the drink.

Both of us had big bills, as you might expect, if only because we planned on doing a lot of entertaining over the holidays (and not because we eat and drink a lot ourselves, you understand). Unbeknownst to each other, we both whipped out our Nectar cards (which run off the same account) and asked for the full credit balance - some 5500 points, worth £55 - to be taken off our shopping bills.

The computer couldn't handle two near-simultaneous transactions drawing down the full balance - and allowed them both to go through! Not until we got home did we realise that we'd struck a bargain.

Fortunately, the next time we went to Sainsbury's and presented a Nectar card, we weren't arrested for committing a heinous computer crime. Instead, our till receipt showed a balance of minus 5500 points.

And so, for the last six months, every point we've earned has gone straight into repaying what was, in effect, a £55, interest-free, unauthorised overdraft.

Colleagues suggested that this had the makings of a modern-day Great Train Robbery, if you could upscale it. Not so sure. Do you know how much money you have to spend at Sainsbury's in order to earn 5500 points in the first place? There must be cheaper ways to commit a crime.