Platforms comply just enough to avoid being blocked, leaving the regulator chasing debt.
Ofcom senior officials have said that most fines issued under the Online Safety Act remain unpaid, highlighting limitations in the comms regulator's enforcement powers.
The regulator's director of enforcement, Suzanne Cater, told the House of Lords Communications and Digital Committee that although another payment arrived this week, "realistically the majority have not been paid."
Ofcom has imposed fines totaling more than £7 million on 11 service providers under its OSA powers so far, but when asked, it refused to specify exactly how many have not paid, nor detail the payment that came in this week.
Oliver Griffiths, group director at Ofcom, said the regulator's enforcement action had primarily focused on smaller companies in the pornography industry. Its largest fine under the OSA, for example, was the £1.4 million penalty imposed on 8579 LLC in February.
Ofcom plans to pursue larger companies, which Griffiths said should make difficulties collecting fines less pronounced.
Asked why it had not collected more of the fines, Ofcom officials pointed to the limits of its powers and the ways online platforms structure their businesses to evade enforcement.
Cater said the regulator was beginning to exercise its powers to hold senior managers personally liable in certain circumstances.
Griffiths said some services had complied after being fined but failed to pay the penalty.
Despite Ofcom's defense of its enforcement record, Griffiths said its own tracking metrics left him "underwhelmed" by the OSA's effect on online safety so far.