The Gift Aid Small Donations Scheme is predicted to have been worth £21m to charities in 2014/15, £2m less than originally estimated, according to the latest HM Revenue & Customs figures.
The December estimate for the values of GASDS to charities in 2014/15 was £23m – this has now been revised down by £2m.
Launched in April 2013, the GASDS allows charities to claim Gift Aid-like relief on up to £5,000 of small cash donations a year without individual paperwork.
The government said the scheme could be worth hundreds of millions of pounds for charities, yet it got off to a slow start.
The only other revision made in the new statistics is that the value of tax repayments to charities in 2014/15 has risen by £10m, to £1.2bn.
Because of those revisions, the total estimated relief to charities has increased to £3.31bn for 2014/15, a rise of 8 per cent on the year before.
"The scheme is due to be reviewed next year and we will be urging the new government to review some of the eligibility requirements that have prevented it from reaching its full potential and benefiting many smaller charities."
Further commentary on the statistics is available from HMRC here.