PM warns web firms, block child porn or I'll change the law Concern: Today David Cameron appeared on BBC1's Andrew Marr Show and said 'I am concerned as a politician and a parent' about child porn on the web Demands: In a speech in London tomorrow, Mr Cameron will tell the internet firms to develop the plans by the autumn or face new laws forcing them to do as he says Mr Cameron's initiative follows a meeting at Downing Street last week with the parents of Tia Sharp and April Jones. The parents of murdered schoolgirls Tia Sharp and April Jones met with David Cameron to plead for him to tighten controls on child abuse images online. Mark Bridger, was found guilty of abducting and murdering five-year-old April Jones in Powys last October. Bridger will spend his whole life in prison after he was found guilty of killing April in a sexually motivated attack. Sitting next to her mother Coral, April's father Paul Jones said: 'Everyone knows the Tia and April stories. What we are trying to do is stop it being another child. We never want another family sitting here having suffered the same thing,' reported The Sun. Stuart Hazell, admitted murdering 12-year-old Tia Sharp in August 2012. Hazell, 37, who was jailed for a minimum of 38 years in May, had sexually assaulted and murdered Tia when she stayed the night at the house. Her mother Natalie, who attended with her partner, told Mr Cameron during the 30-minute meeting at No. 10: 'It's a triangle - the people uploading, the people letting them upload and the people looking for it. We need to knock the first, second and third parts of this triangle down like bowling pins. The Prime Minster told the couples he had changed the locks on his iPad after he walked in on his daughter watching a video of how to make a bath bomb. I came down and she was watching a YouTube video which luckily was someone making a bath bomb. It could have been something completely different. The Prime Minister told BBC1's Andrew Marr Show he was prepared to bring in new laws if necessary. He said: 'I'm concerned as a politician and as a parent about this issue, and I think all of us have been a bit guilty of saying: well it's the internet, it's lawless, there's nothing you can do about it. 'And that's wrong. I mean just because it's the internet doesn't mean there shouldn't be laws and rules, and also responsible behaviour.' He welcomed the steps already being taken by internet firms, but added: 'There is this problem ... that some people are putting simply appalling terms into the internet in order to find illegal images of child abuse. 'And, remember, every one of these pictures is a crime scene and they're getting results. I think it's wrong that they should get results and we need to have very, very strong conversations with those companies about saying no, you shouldn't provide results for some terms that are so depraved and disgusting, I can't even say them on your show. 'And that, I think, there's going to be a big argument there, and if we don't get what we need we'll have to look at legislation.' He added: 'Look, I believe in free speech, but free speech doesn't mean you have the right to incite murder, it doesn't mean you have the right to incite child abuse. 'So it's about companies wanting to act responsibly. If you think about it, there's really a triangle here. There are the people uploading the images. We've got to go after them. There are the people looking at the images. But there is also in this triangle the companies that are enabling it to happen, and they do need to do more to help us with this. In his speech, Mr Cameron will hail the fact that from this month, anyone trying to log on to a child abuse site will receive a warning that the site contained illegal images and has been taken down