Cybersecurity for Accountants and Bookkeepers in the UK

Accountancy firms are data controllers under UK GDPR, responsible for protecting client financial data. The ICO expects appropriate technical controls including encryption, access controls, MFA, and breach notification procedures. Failures can result in fines and professional sanctions. Cyber Essentials certification provides a recognised baseline that supports ICO compliance.

Attackers use phishing emails impersonating HMRC or software providers to steal credentials for Agent Services accounts. Once compromised, these accounts can be used to file fraudulent tax returns or access client data. MFA is now mandatory on HMRC Agent Services accounts — firms without it face both security and compliance risk.

BEC attacks impersonate clients, directors, or suppliers via email to redirect payments or request sensitive financial data. Accountancy firms are targeted because they have authority over client payroll and payments. AI-generated phishing makes BEC increasingly convincing. Advanced email filtering with impersonation detection is essential for practices of all sizes.

While not legally mandatory, Cyber Essentials is strongly recommended by the ICAEW and increasingly expected by enterprise clients. Certification demonstrates to clients that your practice has baseline security controls protecting their financial data. It also reduces the risk of a successful attack by up to 80% against the most common cyber threats.

Cloud accounting platforms should be secured with MFA on every user account, strict access controls limiting client data visibility to relevant staff, regular review of third-party app integrations, and monitoring for unusual login activity. AMVIA configures and monitors these platforms as part of its managed cybersecurity service for UK accountancy practices.