Britain needs better internet laws to stop online abuse that may be creating a nightmare for society in future, Maria Miller, the Conservative former culture secretary and equalities minister, has said.

The senior Tory MP, who now chairs the Commons women and equalities committee, said the government needed to wake up to some of the problems the internet was creating, from vile abuse on social media to easy sharing of violent explicit images among young people.

Miller successfully pushed the government to create a new offence of revenge pornography in 2014, outlawing the distribution of a private sexual image of someone without their consent and with the intention of causing them distress. In the same year, ministers quadrupled the maximum six-month prison term for internet trolls targeting people with offensive or threatening material to two years. The time limit for prosecutions has been extended to three years.

However, the MP argued the laws around abuse and harm on the internet could be updated further and internet companies could do more to act against threatening and abusive material online.

“We need better laws and we need better enforcement. Government needs to stop allowing internet providers from hiding behind arguments about the protection of free speech,” she said.

Miller said people had tried to talk her out of trying to get the law changed to create a specific offence of revenge pornography, some by saying it was already illegal. “It was quite clear after talking to victims and the police that the complex set of existing and sometimes overlapping legislation made it difficult for the police to take meaningful action,” she said.

Her concerns echo those of Stephen Kavanagh, the chief constable leading the fight against digital crime, who earlier this year called for new legislation to tackle an “unimagined scale of online abuse” that he said was threatening to overwhelm the police service.

Kavanagh, who heads Essex police, said: “There are crimes now taking place – the malicious use of intimate photographs for example – which we never would have imagined as an offence when I was a PC in the 80s. It’s not just the nature of it, it is the sheer volume,” he said.

He spoke to the Guardian two days after the England footballer Adam Johnson was found guilty of sexual activity with a 15-year-old girl, having groomed her via a series of WhatsApp messages.

“No police chief would claim the way we deliver police services has sufficiently adapted to the new threat and harms that the internet brings,” Kavanagh told the Guardian at the time. He said new offences such as revenge porn were welcome, but the law overall was too piecemeal.

The Guardian reported on Monday that Google, Facebook and Twitter were talking to grassroots organisations around the world to organise a global counter-speech movement against the violent misogyny, racism, threats, intimidation and abuse that flood social media platforms.

The tech firms are reaching out to women’s groups, non-governmental organisations and communities in Africa, the Americas, India, Europe and the Middle East as the scale of abuse online continues to increase.

Miller said she thought part of the problem was an incorrect “philosophy in government that the internet does not create new offences” and a failure among some internet companies to flag up criminal behaviour online.

“The problem is rooted in the fact that many internet companies won’t acknowledge that they can challenge, and should stop, criminal behaviour, saying they are just like the postal service and can’t help that people use their services for criminal activity, that it’s not their problem. It is their problem and we need to sit up, take notice and realise that we are creating a nightmare future.”

Some of Miller’s concerns about online abuse chime with those of Yvette Cooper, the Labour MP and former leadership candidate who backed a Reclaim the Internet campaign in December against “sexist abuse, misogyny, racism and violent threats online”.

Miller said: “I recently did an interview on Australian television about gender fluidity. You have to delete some of it but I retweeted one of the vile comments that I received and said: ‘Do you think this is an appropriate way to behave?’ I got back a lot of vile abuse.

“People are unleashing their inner venom in a way I just do not think is healthy for society. We have got to have an honest debate about this. Too many people in government are saying it is all about freedom of speech and it is not.“Threatening, homophobic, racist, sexist abuse online can actually stifle debate, lead to censorship – with some individuals not willing to say things that might provoke abuse.”

The former cabinet minister has wider concerns about explicit material being viewed by children at the click of a button, which has prompted her to campaign for compulsory sex education in schools.

While some will argue that taking down websites is the thin end of the wedge towards the erosion of free speech, she said: “I think the thin end of the wedge is that a 10-year-old can view pornography at the flick of a switch. I don’t think that is right. And there is still little policing of very abusive websites.”

The Guardian’s The web we want series launched on Monday to explore the darker side of online comments and efforts to foster better conversations online. It has included research on the Guardian’s own below-the-line comment threads.