I’m just back from a short holiday, which went a bit like the General Election: we booked Portugal, but got Aviemore. The culprit was, of course, the volcanic ash cloud.

There’s not much you can do about an Act of God, but it’s quite exceptionally frustrating when you’re also dealing with the Acts of Sods. It turns out that – surprise! – some firms are complete bastards, so even when they’ll cover you for volcanic eruptions, they won’t actually cover what you think they’re covering.

I’ll spare you the minor ones, but this one struck me as a contender for the Big Book of Bastards: my in-laws, who booked the accommodation using their credit card, have been informed by their insurers – Royal Bank of Scotland – that RBS will only pay for two-fifths of their costs.

The problem, apparently, is that while RBS’s travel insurance covers any travel you book with your RBS card, the cover only extends to the account holder(s), not the entire party – so in our case, I’m supposed to claim the remaining three-fifths of the cost from my own travel insurance.

Problem is, the booking wasn’t in my name, and it wasn’t booked using my card. So I can’t claim it on my travel insurance at all.

I’m sure that with sufficient threats they’ll pay up eventually, but it does demonstrate that the whole point of travel insurance (or any other insurance) is to find ways not to pay in the event of a claim. I know that the B in RBS stands for Bastards, but I’m still quite shocked at just how bastard-y RBS’s travel insurance wing has been.

The point to all this? With Mount Unpronounceable kicking off for the forseeable future and perhaps bringing its friends to the ash cloud party too, don’t just buy travel insurance on price or on headline benefits. Look for the loopholes.