HM Revenue & Customs has drawn up proposals to change the law so that donors, rather than charities, would be penalised if a donation contravened substantial donor legislation, according to sector accountants and lawyers.
The legislation is designed to ensure that people do not materially benefit from donating to charity and then receiving payments or other benefits in kind in return.
Charities are currently vulnerable to taxation if they make payments to donors who give them £25,000 or more in a single year, or to any person or business associated with them.
Sector experts are concerned that, as things stand, charities could unwittingly be penalised for making legitimate transactions.
Nick Brooks, head of not-for-profit at accountants Kingston Smith, said he was confident of a "good, solid result for the sector" after attending talks with HMRC. "The whole emphasis has changed," he said. "Before the onus was on the charity to ensure that no wrongdoing had occurred. Now the onus is on the donor."
Nicola Evans, a senior associate at charity lawyers Bircham Dyson Bell, said HMRC had agreed the law would only apply if there was a "predetermined agreement" that donors would receive some benefit in exchange for their gifts.
An HMRC spokesman said proposals it had put forward were widely welcomed by the sector, but that draft legislation based on those proposals had not yet been drawn up.