Schemes that encourage people to write wills, both free and paid-for, have been run by individual charities before. But the campaign, Free Wills Fortnight, is the first time such a coalition has been established to help people get their wills written for free.
The charities involved are Age Concern England, Barnardo's, the Blue Cross, the British Lung Foundation, Breakthrough Breast Cancer, Diabetes UK, Plan UK, the Royal British Legion, Sense and the Stroke Association.
The campaign, which will run from 16 to 30 September, will offer members of the public aged 55 and over the opportunity to have their wills written or updated for nothing, using the services of participating firms of solicitors in England and Wales.
Although there is no obligation on those who take up the offer to leave a charity gift in their will, and no requirement that legacies must be to members of the scheme, it is hoped the project will still generate pledges for the signed-up charities.
The scheme was created by Stephen Maund, managing director of Capacity Marketing for Charities, which has previously run free-will campaigns for individual organisations.
Maund wrote to the top 100 charities, inviting them to participate. Keen to avoid competition, he accepted as members those that were the first to reply from different cause areas.
Martin Runchman, legacy manager at Barnardo's, said: "The scheme not only encourages people to leave legacies, but also highlights our work."
The charities pay for the service provided by the solicitors, which offer a reduced rate in return for the publicity it generates for them.
Maund said that by banding together the charities can reach a much wider audience geographically. About 40 solicitors working in 12 areas across England and Wales, including Nottingham, Plymouth and Swansea, have signed up.
An advertising and PR campaign will be mounted and a website is under development. This will direct those interested in the offer to the nearest participating solicitor. Each charity will run parallel marketing campaigns in the regions to generate interest in their work.