The name of the Telephone Preference Service doesn't exactly tell you what it does. Whether that's deliberate or not, more and more people are finding out that it does something fairly life-enhancing - it stops you getting cold calls. Nearly 6 million people have signed up, and the number is growing.
The problem for charities is they, like credit-card companies and glazing firms, get their calls blocked by the TPS. And now they're so worried at the rate of opt-out that they're arguing that they should be exempted from the restrictions.
One of the arguments made by the Institute of Fundraising, among others, is that when people sign up for the TPS they aren't aware that it will prevent them receiving calls from charities. If that's the case, surely the Direct Marketing Association, which runs the TPS, should find a way of telling them. If people knew they were excluding charities - the argument goes - they would change their minds so they could continue enjoying the privilege of having the children's bathtime interrupted by requests to donate to the distressed gentlefolk's welfare association.
In an age of declining donations, it's understandable that charities should seize on any method that offers the hope of a revival in giving.
But they should, as with face-to-face fundraising, beware of clinging too hard to methods that, in the long term, can alienate potential supporters.
Clearly there's a case that people signing up for the TPS should be given the opportunity to tick two boxes - one for commercial firms, another for charities. But there's a strong chance they'll tick both, and the difficult search to find ways of persuading people to give without hassling them will have to go on.