If charities are to maximise the generosity of the British public and combat the perceived “compassion fatigue” they need to start demonstrating the impact of their work more effectively, sector leaders warned last night.

Chief executives Stephen Ainger of CAF, Brendan Gormley of the DEC and Nicholas Young of the British Red Cross were speaking at an event organised by The Beacon Fellowship to discuss “charitable giving post Tsunami”. They were joined on the panel by broadcaster, Martin Lewis; Lord Bell of Belgravia, chairman of Chime Communications, and Lord Deedes of the Daily Telegraph.

Stephen Ainger said: “Although the response from the British public was overwhelming, there have already been reports of a fall in giving to other causes elsewhere in the UK. We also know that 9/11 did not lead to a rise in donations and that over the last 15 years levels of charitable giving have remained flat.

“What is clear is that we need to show the public the difference being made by their money –not only by showing how much we’ve spent and what we’ve spent it on but what impact its had to the lives of the people we’re helping. We risk levels of income dropping if we don’t.”

Lord Deedes highlighted the need for charities to supply news worthy stories to the media. He said: “The Tsunami has bought home the strong link between media coverage and giving. This is a powerful link that will work for other charities too. It imposes on them the need to provide stories of interest to the media.”

The total raised by the Tsunami appeal is expected to reach £300m, of which £250m came from individual donors. It represents the largest single response to an appeal in the history of the DEC and is equal to almost half the annual amount given to international aid charities.