The Giving Campaign has published guidance on increasing take-up of Gift Aid at sponsored events.
Although many charities already include the Gift Aid option on their sponsorship forms, some are unable to claim the tax back due to illegible or deficient information.
The guide, available online or as a leaflet, contains suggestions on how to ensure inclusion of details that are frequently omitted, such as the donor's home address.
It is based on the results of a pilot study that aimed to identify the most brief and accessible forms. Four different designs were tested at three sponsored events. The two most successful ones are currently detailed on www.giving campaign.org.uk.
"Money raised by claiming Gift Aid on sponsored events makes a huge difference to us," said Jenny Edwards, head of events at Macmillan Cancer Relief.
"In 2003 alone, we claimed back £35,000 in Gift Aid on behalf of our London Marathon runners."