A lawyer representing the online message board 4chan says it won't pay a proposed fine by the UK's media regulator as it enforces the Online Safety Act.

According to Preston Byrne, managing partner of law firm Byrne & Storm, Ofcom has provisionally decided to impose a £20,000 fine "with daily penalties thereafter" for as long as the site fails to comply with its request.

"Ofcom's notices create no legal obligations in the United States," he told the BBC, adding he believed the regulator's investigation was part of an "illegal campaign of harassment" against US tech firms.