Card company Studio51, which donates 51 per cent of the sale price of cards to nominated charities, claims to be the first to receive a green light from HM Revenue & Customs to claim Gift Aid on card sales.
Gift Aid cannot usually be claimed because it applies only to donations and not to sales. However, Studio51 has developed a system that allows Gift Aid to be claimed.
When supporters buy cards though the company's website, they will effectively pay 49 per cent of the sale price to the company and pay the remaining 51 per cent to charity as donations.
They will be asked to tick a box to say they are UK taxpayers, allowing Gift Aid to be claimed on the donations. The system will operate from next spring.
"Our aim is to up the ante on Christmas card donations from the measly 5 or 10 per cent that's currently available from high-street retailers," said Alan Hawkes, founder of Studio51.
He added that it would be difficult for high-street stores to replicate the system because they would need to collect donor information for an audit trail. However, Mark Astarita, director of fundraising at the British Red Cross, said simplifying Gift Aid should be more of a priority. "We need to simplify the system rather than force fundraisers to come up with yet more wheezes to find ways to collect Gift Aid," he said.
"Most charity catalogues have a tick box that lets people give donations that are Gift-Aidable."
A spokeswoman for HMRC said: "We are unable to comment on individual circumstances. However, we can confirm that Gift Aid applies only to actual gifts of money, not to the purchase of goods."
Studio51 will partner with up to 200 charities when it rolls out its Gift Aid scheme, but hopes to increase this.
It also intends to extend its services to birthday cards and other ranges online next year.