For as long as many can remember, charities have been supplying supporters with envelopes with a box in the top right corner saying that a stamp is not necessary, but using one will save the charity money.
The mental debate over whether to attach a stamp - have you got one? how important is this, really? - is one of the little rituals of donation.
In 2008, an investigation by Third Sector showed that the Royal Mail was often being paid twice for processing charity mail - once by the donor through the stamp, and again by the charity through the Freepost marking on the envelope. This was because letter-processing machines introduced three years earlier recognised the Freepost marking, but not the stamp.
The response of the Royal Mail was - and still is - that if charities keep Freepost envelopes that reach them with stamps on them, it will refund the cost of the stamps on presentation. At least one large charity does this, but is it widespread or cost-effective?
Eighteen months on, it turns out that many charities are still using the box on their envelopes, including big names such as Oxfam, CRUK, the Salvation Army and the RSPB. Why? Without being too dramatic, the practice is in some cases potentially deceptive of donors, causing them unnecessary expense. The straightforward solution is to stop using both Freepost and the box so donations become letters that have to be stamped and posted like any other.
Charities might hesitate to stop using Freepost for fear that the cost of a stamp, or a donor's inability to find one when acting on the impulse to give, might mean that the gift doesn't get sent at all. If charities continue to use Freepost, they could always just remind donors on the donation form or the envelope that the charity has to pay postage - which might produce an increase in the intended donation larger than the cost of the stamp.