At a Regulating AI Conference last year, it was confirmed that an AI Assurance regulatory framework is due to be published in the first half of 2022. During the conference, an AI Assurance Ecosystem Roadmap was published by the Centre for Data Ethics and Innovation (CDEI).
Other references that may prove useful are:
EA: How Quality Infrastructures support transition to Industry 4.0 International Laboratory Accreditation Cooperation (ilac.org)
Standards for the Fourth Industrial Revolution (publishing.service.gov.uk)It is believed there is a role for accreditation in the world of AI Assurance, but it is hard to determine at this stage.