TalkTalk and BT have rejected requests from the UK's Gambling Commission to impede access to unlicensed gambling websites.
The Commission was founded under the Gambling Act 2005 to regulate commercial gambling in the UK, and had sought to place restrictions or warnings on the sites that people could access through their internet connection - something that ISPs have the power to introduce.
However, BT and TalkTalk - two of the UK's biggest broadband providers - have resisted the request, and said the Commission will need to seek a court order before they comply.
The request had asked that the ISPs insert a warning before an internet user clicks on a link to a gambling page that is unlicensed, which cautions them about the nature of the site.
It is similar to how broadband providers currently tackle websites that are deemed to facilitate piracy or depict illegal images, and would place the gambling sites in a similar bracket as those that contain pornographic imagery.
It is possibly this reason that has led BT and TalkTalk to resist taking action, coupled with the fact that the Commission has no firm jurisdiction over offshore websites.
Under the proposals, the 'splash pages' would be visible to every user - not only those that have enabled the ISP's Parental Controls, which are an optional system.
Speaking to the FT, a commission spokesperson commented: "We have been exploring the internet service providers' approach when faced with clear evidence that sites are unlicensed and engaged in illegal activities.
"At this stage we are just exploring back-up options as we do not expect illegal sites to be a major issue, given the attractiveness and width of the legal offer."
In response, the ISPs have argued that it is not their duty to police the internet and decide what their users can and cannot access, with TalkTalk calling for a "proper legal framework" to be put in place, similar to the system for sites that infringe copyright.