Concerns have been expressed that charities may suffer as a result of contested Wills.
Commenting on the issue, Mark Watts, chief executive of the Royal Society for the Prevention of Cruelty to Animals (RSPCA) told Third Sector that such organisations may have to "cave in" when legacies are disputed.
He made his remarks ahead of the forthcoming appeal being made by the society in the case of Christine Gill, who successfully challenged her mother's stipulation that she would leave £2 million to the charity.
A judge ruled that the mother had been bullied into leaving her money to the RSPCA - which describes itself as the "leading animal welfare charity".
Mr Watts stated: "My biggest fear is that the threat of costs ... will put a lot of charities off going down the road of fighting, even if they are justified."
He added that it would be a "bridge too far" for some charities.