The survey, which was carried out by telephone marketing company Pell & Bales, involved people posing as naive charity donors to discern how effective charities are at responding to individual callers.
Pell & Bales approached 39 of the largest 100 charities - including Unicef, ActionAid, Christian Aid, Oxfam and the RNLI - by email, post and telephone in order to do three things: request information, make a complaint and donate money.
Out of 117 attempts to pledge a monthly direct debit donation, only 66 were successful. And one charity took 210 days to return the confirmation and thank the donor.
There was great variation in charities' responses to the different methods of email, post and telephone.
Karl Holweger, chief executive of Pell & Bales, said: "A handful of bodies are truly excellent at creating responsive relationships, but a larger number seem virtually inert.
"These are the grateful dead. They need to wake up."
He said the responses amounted to a "subliminal message" to donors that the charities don't really need their money.
Only 42 per cent of donors were asked to Gift Aid their donations, down from 46 per cent the previous year. Just 8 per cent offered Gift Aid across all three channels.
However, the politeness of charities is rising, with two-thirds of telephone donors thanked, up from one-third the previous year. But only 13 per cent thanked across all three channels, and the same amount failed to thank at all.
The survey was conducted between May 2004 and January 2005.
- See Editorial, page 20, and News, page 3.