If 1 per cent of people who do not leave charitable gifts in their wills were persuaded to do so, it could raise an extra £109m a year, according to the 2019 Legacy Trends Update.
The report, produced by the legacy information provider Smee & Ford and published today, says that in 2018 charitable bequests in wills hit £3bn for the first time, as reported earlier this month.
But it adds that this total figure of £3.364bn had been inflated by a single "massive" legacy of £435m to the Capricorn Foundation.
Estates that included charitable gifts were worth a total of £17.9bn, meaning 16.7 per cent of the estates’ net worth went to charity. The report says that if all estates included charitable gifts it would be worth an additional £10.9bn to the sector.
"Using the total number of probated estates in 2018, if just 1 per cent of those people included gifts to charity in their wills it would have raised an additional £109m for charities," the report says.
The report says that 6.3 per cent of the population leave bequests to charity in their wills, with a total of 37,856 estates including charitable gifts, up from 37,364 in 2017.
These estates included a total of 123,235 charitable bequests, an increase from 122,849 the year before, and the average charitable estate included three separate bequests.
The increase in bequests, the report says, could be connected to the death rate.
"The more deaths there are in any year, generally the greater the number of charitable estates," it says.
"We have seen an increase in the number of annual deaths in the UK in recent years, which has helped to increase both the number of charitable estates and aggregate legacy values."
But despite the rise in the number of charitable bequests, the total value of the estates that left money fell by £500,000, from £18.4m in 2017 to £17.9m in 2018.
"For the first time in recent years the average estate value for charitable estates has decreased, which can be explained by the drop in house prices during 2018," the report says.
The majority of bequests to charity are residual bequests, in which a percentage of the value of the estate, which often includes property, is left to charity, rather than a fixed amount, meaning the housing market can affect the amount of money charities receive, the report says.