Milly Dowler's family have warned David Cameron that his planned legal reforms would leave ordinary people without the power to challenge abuses.
The murdered schoolgirl's family is to receive £2m from the News of the World over the hacking of her mobile phone in 2002, while Rupert Murdoch is to donate a further £1m to charity.
In an open letter to the Prime Minister, they say they could not have reached their settlement without the no win, no fee system, which enables claimants to take insurance against losing a case. "Without that we would not have been able to start a case, or threaten it," Milly's parents, Sally and Bob, and her sister, Gemma, write.
"We are sure you do not want to go down in history as the Prime Minister who took the rights away from ordinary people so that large companies could print whatever they like and break the law without being able to challenge them."
Ministers argue the current system is fuelling a compensation culture as claimants who are unsuccessful will not be out of pocket. Under the plans going through Parliament, claimants who use no win, no fee will have to pay 25 per cent of their legal costs irrespective of whether they succeed.
A government spokesman said: "In order to ensure the no win, no fee cases continue to provide fair access to justice for all, we have to make changes. By balancing the costs more fairly between the claimant and defendant, these changes will ensure claimants will still be able to bring deserving claims and receive damages where they are due. They will make the no win, no fee system sustainable."