TV presenter Gabby Logan has spoken of her frustration over false rumours on Twitter about her private life.
She said she would do everything she could to protect her family but said she could not take action against everyone using the social networking site to spread lies.
The 38-year-old host of the BBC's Final Score said: "My name was brought into this mess with someone else, accusing me of something which is clearly not true and the newspapers knew this and they published a story saying it wasn't true, but it is happening because super-injunctions are in place and people are trying to guess who is involved."
Speaking on ITV's Daybreak programme to promote National Schools Sports Week, she said: "Newspapers clearly think it's a curtailing of the freedom of speech, which it is, but how do you police the internet?"
The mother-of-two, married to former Scotland rugby international Kenny Logan, said her reputation had been damaged by the false allegations, which linked her to former footballer Alan Shearer.
She told presenter Adrian Chiles: "To tell lies about people, and lies about their family - that's where it ends for me. I protect my family to the end and I'm not going to have that, but clearly I can't go around suing everyone on Twitter. It is muddying the waters for people who have done nothing wrong."
Logan was speaking after another celebrity became the victim of false rumours on Twitter at the weekend.
An anonymous user claiming to expose famous people who have obtained injunctions to prevent reporting about their private lives wrongly suggested socialite and campaigner Jemima Khan had stopped publication of pictures of her with Top Gear presenter Jeremy Clarkson. Ms Khan responded on Twitter by posting the message: "Rumour that I have a super-injunction preventing publication of 'intimate' photos of me and Jeremy Clarkson. NOT TRUE!"
The user who made the false claim had used the microblogging site, which can be read by anyone online, in an attempt to get around gagging orders taken out against the media.
There is growing disquiet about use of injunctions and "super-injunctions" - whose very existence cannot be reported - to prevent publication of details about the private lives of well-known people. Culture Secretary Jeremy Hunt said on Tuesday that Twitter was "making a mockery" of privacy laws and pledged to bring regulations up to date.