Five Questions On: Comparison sites

They're the consumers' friend, yes?

Up to a point. It's true that they have helped millions of people get into the habit of switching regularly to save cash on everything from mortgages, to credit cards, to energy deals – but accusations were raised this week that they hide the best deals from consumers.

How do they conceal the best deals?

Critics say that comparison sites ask users if they want to see tariffs they can switch to "today" or "now". Then when people click "yes", as they invariably do – after all, who wants to wait to switch? – the sites filter out the deals that do not earn them a big commission from the company gaining the new customers.

Why do they do that?

To increase their profits. Look, these are multimillion-pound businesses, not consumer champions. One chief executive said: "They position themselves as a service when in reality they are profit-maximising sales organisations."

So can't I trust them?

In general, comparison sites have been a force for good, in that they do help people to switch and save money. But that doesn't mean you'll be getting the best deal from them, especially if they don't show you all available offers. There are also concerns that they encourage people to choose on price, when doing so can be a costly mistake. If you think cheapest is best, then you need to think again; the best is the deal that offers the greatest value. For instance, a 0.99 per cent mortgage launched on Monday by HSBC is currently the lowest rate charged in the market. But the deal is actually more expensive than others because it has a £1,999 fee.

So what's the answer?

Comparisons should be based on the total cost of the deal, including all fees, charges and commissions paid. And commissions – which vary from £40 to £70 per customer – should be clearly signalled and detailed.