26 United Nations Principles and Guidelines on Access to Legal Aid in Criminal Justice Systems (g) To allow, in accordance with national law and regulations, courtaccredited and duly trained paralegals to participate in court proceedings and advise the accused when there are no lawyers available to do so. Guideline 15. Regulation and oversight of legal aid providers 69. In adherence to principle 12, and subject to existing national legislation ensuring transparency and accountability, States, in cooperation with profes‑ sional associations, should: (a) Ensure that criteria are set for the accreditation of legal aid providers; (b) Ensure that legal aid providers are subject to applicable profes‑ sional codes of conduct, with appropriate sanctions for infractions; (c) Establish rules to ensure that legal aid providers are not allowed to request any payment from the beneficiaries of legal aid, except when authorized to do so; (d) Ensure that disciplinary complaints against legal aid providers are reviewed by impartial bodies; (e) Establish appropriate oversight mechanisms for legal aid provid‑ ers, in particular with a view to preventing corruption. Guideline 16. Partnerships with non‑State legal aid service providers and universities 70. States should, where appropriate, engage in partnerships with non‑State legal aid service providers, including non‑governmental organizations and other service providers. 71. To this end, States should take measures, in consultation with civil society and justice agencies and professional associations: (a) To recognize in their legal systems the role to be played by non‑State actors in providing legal aid services to meet the needs of the population; (b) To set quality standards for legal aid services and support the development of standardized training programmes for non‑State legal aid service providers;