When signing up for fixed line broadband with any of the biggest ISPs you have to make a choice between filtered and unfiltered. As the GP said, mobile broadban

When signing up for fixed line broadband with any of the biggest ISPs you have to make a choice between filtered and unfiltered. As the GP said, mobile broadband has filtering enabled by default and has done for years. Source: Am in the UK & have opted out of filtering. All fixed line ISPs allow toggling the filter bias their online control panel, or by clicking a button when signing up online. Mobile ISPs vary - O2 mobile require you give your card details.