Gerry McCann, the father of missing youngster Madeleine McCann, has urged politicians to implement the conclusions of the Leveson Inquiry in full.
At a news conference organised by the pressure group Hacked Off, he called for any new independent regulator of the press to be underpinned by law, arguing that "the sick culture has not changed, and they [the press] can't be trusted to change it of their own accord".
During the news conference, which was held ahead of the publication of the Government’s response to Lord Justice Leveson’s report, Dr McCann spoke of the treatment he and his wife Kate experienced at the hands of the press.
"Stories were published saying our daughter was dead - over and over again, with no evidence," he said.
"Rumour was dressed up as the truth and downright lies became front-page news.
"Our experience was extreme, but it was a consequence of the same sick culture that led to the abuse of many other people.
"An insatiable hunt for headlines combined with a total lack of respect for other people. The mentality that can turn a family’s distress into cold, hard cash. Profit from misery.
"In our case it led to the sacrifice, not only of the truth, but of our dignity, privacy, well-being and most importantly the search for our missing daughter, Madeleine."
The Leveson Report proposed that a new press regulator needed statutory underpinning if it were to be truly independent - but the Prime Minister has argued against the need for new legislation to bring the press to heel.
It is expected that the Government will instead propose to set up the new regulator under Royal Charter - a means of incorporating an organisation, and making it in and of itself a legal entity.
Hacked Off says that would not be satisfactory as ministers would be able to amend the Charter far more easily than if the regulator was created through an Act of Parliament.
"This is an opportunity for our elected MPs, whose reputation with the British public is at an all-time low, to redeem themselves," said Dr McCann.
"Any watering down of the Leveson plan now, whether in a Bill or Royal Charter, would be like surrendering to the press and saying the whole Leveson process was a waste of time."
Madeleine was nearly four when she vanished from her family's Portuguese holiday apartment in Praia da Luz in 2007 as her parents dined at a nearby restaurant with friends.
Both Gerry and his wife Kate were considered suspects by Portuguese police before being exonerated.