The value of some of the largest legacies left to charities will fall by between 10 and 15 per cent over the next 12 months, according to research programme Legacy Foresight.
According to the charity-funded scheme, residual bequests - the amount left to charity after named beneficiaries are accounted for - were the most affected by changes in the economy. The average legacy value is currently £54,400.
The prediction was included in the latest figures from Legacy Foresight's Legacy Monitor report, which it developed with software firm Clearwater Consultancy.
Data included in the report is provided by a consortium of 38 charities including CRUK, the British Red Cross and the NSPCC.
It revealed the charities' combined legacy income growth in 2008 was 1.7 per cent, compared with 10.3 per cent in 2007.