Fundraising experts have questioned the findings of a report that shows charitable giving in 2011/12 fell by £2.3bn in real terms.
The UK Giving 2012 survey, published today by the Charities Aid Foundation and the National Council for Voluntary Organisations, says that total donations in 2011/12 were down by 20 per cent on 2010/11 figures, to £9.3bn.
But the Institute for Fundraising said that the figures did not match the experiences of its members, who say donations have either increased or remained flat.
Peter Lewis, chief executive of the IoF, said: "This is an interesting new set of data and we need to look at it more carefully and do some analysis to see what is behind the reported decline in giving.
"As far as we are aware it doesn’t reflect the experience of our members. Charities that have spoken to us say that they have had an increase or giving has been flat at worst.
"Neither does it reflect the experiences of the small charities engaged in our programme funded by the Office for Civil Society, which has demonstrated that organisations that engage in fundraising are able to diversify their income.
"We are keen to understand the data behind the headlines, particularly what types of giving and what types of charity are affected."
Lewis said the dip did not appear to be happening across the board.
"Charities need to look at their own data and monitor their own performance," he said. "We look forward to seeing how this is reflected in the UK Civil Society Almanac, which is based on returns to the Charity Commission and reflects what people gave and not just what they said they did."
The report, which is based on a survey of more than 3,000 people by the Office for National Statistics, says donations were down £1.7bn on 2010/11 in cash terms and £2.3bn when adjusted for inflation.
Cathy Pharoah, professor of charity funding at Cass Business School, said: "A fall of that scale is very unusual and could not be explained by any trends we’ve seen before. It vastly outstrips changes in the economy."
The proportion of people donating to charity in a typical month fell from 58 per cent to 55 per cent over the same period, according to the report.
"Participation has fallen by 5 only per cent, but the fall in giving is much bigger than that," Pharoah said.