Heritage and arts sector organisations including the Museums Association and the Art Fund have joined a campaign against fresh plans to cap tax relief on major charitable donations.

It is estimated £11bn is donated to charities each year, with 45 per cent of the total thought to come from a mere 7 per cent of donors - most of whom are higher-rate taxpayers.

However, the plans from HM Treasury will see a £50,000 (or 25 per cent of income) cap on tax relief imposed, which the campaign said will increase the cost of giving to charities.

Charities Aid Foundation chief executive John Low said: "The Treasury talks as if Britain's most generous charitable donors are simply tax avoiders."

"Treasury officials just have not recognised that there is a world of difference between giving your money away for the public good, and trying to offset tax for private gain."

Art Fund director Stephen Deuchar added: "The cap will discourage the most generous donors at a time when charities are being asked to rely more heavily on their support."

News of the cap on tax relief for charitable donations comes despite plans announced by the government in 2010 to create "a new generation of philanthropists" to benefit the arts sector.

Details: www.giveitbackgeorge.org

Image: Britainonview/Simon Kreitem