The BBFC is the regulator in the UK - their website provides extensive information about how age-verification for online pornography is implemented and additional details on on how AV arrangements will work can be found here. The official UK Government press release also provides helpful and accurate information.
NOTE: These FAQs were written by Liz Walker with the support of John Carr from the UK Children's Charities' Coalition on Internet Safety. A number of the FAQs were first published by Culture Reframed. Liz is Director of Health Education at Culture Reframed and also Deputy Chair of eChildhood.