The Helplines Association has warned that a proposal to make calls to 0800 numbers free to callers from mobile phones as well as from land lines could cost some charities so much that they might be forced to block calls from mobiles.
At present calls to 0800 numbers from most land lines cost the caller nothing while the recipient pays about 2p, but 0800 calls from mobiles are charged to the caller. Many charity helplines use 0800 numbers because they are toll-free from land lines.
Last week the telecoms regulator Ofcom launched a consultation on proposals to simplify the pricing of numbers beginning with 03, 08, 09 and 118. Under the proposals calls to 0800 numbers would be free from mobiles as well, but organisations receiving the calls, including charities, would have to pick up the bill.
Calls from mobiles currently cost as much as 40p per minute. Deirdre Rusling, the sector development officer at the Helplines Association, said she did not know what the charge to recipients would be, but said many charities in Germany, where it has always been free to call 0800 numbers, had been forced to block calls from mobiles because charges were so high.
"And in Ireland this problem has gradually got worse as the proportion of calls made from mobiles has increased," she said. Calls from mobiles to 0800 numbers in Ireland can cost as much as 70 cents (59p) per minute, said Rusling.
"Here, helplines would suddenly be faced with a massive increase in their phone bill, with no additional funding available to pay for it," she said.
The best solution would be for Ofcom and the mobile networks to agree a scheme that would exempt charity helplines from paying these charges, she said. She emphasised that, overall, the organisation was in favour of the proposals.
The Helplines Association has already set up one agreement with the major mobile networks, with the help of Ofcom, which allows people to call charity helplines for free from mobiles through a special number range. But this is only available to members of the association who pay an administration fee of about £45 for the service.
A spokeswoman for Ofcom said the consultation would be open to ideas from all interested parties. "If there are ideas that stakeholders put forward we will obviously listen to them," she said.
More information on the consultation, which will run until 10 March, can be found here.