By Mark Ward
BBC News Online technology correspondent
Pornography and other adult services are creating big problems for many mobile phone firms.
Sexy SMS chat is popular with many users
Operators are struggling to find ways to stop children and others accidentally stumbling across adult content but they also want to make it easy for those that want to pay for porn to get at it.
This week phone firms, industry analysts and mobile content creators are meeting at a conference in London to debate the ways in which operators can strike this balance.
Networks fear that if they do not quickly find a workable way to handle adult content the Government will impose its own regulations.
Already adult content, which includes pornography as well as violent computer games and other age-restricted activities, is proving lucrative for many mobile phone firms.
But some customers' desire for smutty SMS chat or titillating images creates a headache for the phone operators said Andrew Bud, head of messaging firm Mblox and a board member of the Mobile Entertainment Forum.
"In many ways we are back in the early 1960s and finding what are the bounds of public acceptability of adult content in the new medium," he said.
What mobile firms did not want to do, said Mr Bud, was to make the adult content easy to find accidentally.
"They are trying to find the right balance between editorial freedom and really annoying the public," he said.
But, he said, what the industry also wanted to avoid was an "opt-in" system that had all adult content turned off unless people specifically ask for it.
The industry is already moving to put in place a code of conduct that brands adult content and tries to ensure that children do not get access to it.
The code covers images, video, gambling, games, chatrooms and net access but not premium rate voice and text message services.
The good news, said Mr Bud, was that regulating content on mobile phone networks was much easier than on the net.
There were a limited number of ways that adult content could be inserted into the mobile network, he said, making it straightforward to find and cut off abusers.
He added that because cash usually changes hands when adult content is bought, it can be easy to trace abusers and cut them off from the mobile networks.
Pornographic services could be lucrative for phone firms
Ray Anderson, head of content aggregator Bango, said rating, filtering and blocking systems could also prove much more useful than those used online.
"Mobile telephones are typically allocated to an individual rather than PCs which can have a lot of users," he said, "It can be a much safer environment."
But, he said, blocking and filtering systems need to be flexible so that they can be tuned to different sorts of users such as businesses or concerned parents.
Mr Anderson said he expected to see the emergence of phones specifically made for children that have filters and blocking systems already built in.
As well as debating better ways to handle adult content, some speakers will also be raising other concerns about new phone technology.
Dr Rachel O'Connell, head of the Cyberspace Research Unit at the University of Central Lancashire and an expert on paedophiles' use of technology, said smart phones bring with them a range of new risks that operators need to be aware of.
New technologies bring with them new risks
She said that software tools exist which would allow someone to grab information about a child via their phone and build up useful information about when they were vulnerable.
Dr O'Connell said only a small number of paedophiles are likely to become such keen users of technology but she said the risks had to be taken into account.
"I think we need to understand that perhaps the profile we have of a paedophile is going to morph in lots of ways," she said.
"But," she added, "what's wonderful about the current situation is the mobile telephone industry is much more motivated to take action than the internet industry was."