The charitable will writing scheme Will Aid raised £1.1m in 2017, a drop of £200,000 on the total raised in 2016, the organisations behind the scheme have announced.
The Will Aid event, which takes place in November, sees solicitors waive their fees to write basic wills for people, instead inviting people to make donations of £95 to charity.
The scheme is run as a partnership between solicitors and nine charities: ActionAid, Save the Children, the British Red Cross, Christian Aid, the NSPCC, Age UK, Sightsavers and the development charities Trócaire and SCIAF.
Last year more than 700 firms took part in the scheme, raising £1.1m, according to figures released by Will Aid last week.
But in 2016 the scheme raised £1.3m, with the support of almost 1,000 solicitor branches.
A spokeswoman for Will Aid said: "Will Aid relies on the generosity of solicitors across the UK to volunteer their time and expertise to write wills while waiving their usual fees.
"Last year we saw a slight drop in the number of solicitors participating so, although demand remained extremely high, less of this demand was fulfilled."
The scheme will go ahead in November this year.
"This year – which is our 30th anniversary – we are making a huge push to get even more solicitors involved in this very worthwhile campaign and hope to beat the £1.1m raised in 2017 for the vital work of nine incredible charities," the spokeswoman said.
"There are millions of people across the UK who do not have wills, and Will Aid provides an opportunity to have this crucial piece of paperwork drawn up by a professional."