10 Best Audit & Assurance Firms in London (2026 Verified)

"PwC is highly regarded in London for its comprehensive audit and assurance services, leveraging deep industry knowledge and a robust global network. They excel in providing customized solutions that cater to the unique needs of each client, ensuring compliance while enhancing financial performance. Their proactive approach to risk management and commitment to innovation through technology position them as a trusted advisor in the industry."

"EY has established itself as a leader in audit and assurance in London, renowned for its strong commitment to quality and innovation. The firm employs advanced data analytics and AI technologies to improve auditing processes, providing clients with deeper insights into their financial health. EY's global presence enhances its capability to serve multinational clients while maintaining a local touch, making them a preferred choice."

"KPMG is recognized for its outstanding audit services in London and its deep engagement in various sectors, including technology, healthcare, and financial services. Their focus on digital transformation allows them to provide modern solutions that drive efficiency and reliability in audits. With a positive culture emphasizing professional development, KPMG nurtures talent to enhance client service delivery."

"BDO has carved out a solid reputation in London for its personalized audit services and deep industry knowledge. They focus on mid-market businesses, providing highly customized solutions that align with specific client needs, which sets them apart from larger competitors. Their dedication to fostering strong client relationships ensures a high level of satisfaction and trust."

"Grant Thornton is a key player in the London audit and assurance landscape, particularly noted for its focus on quality and service delivery. The firm combines local expertise with international insights, giving clients a comprehensive view of the market. Their commitment to the UK mid-tier market allows them to tailor services to meet the needs of dynamic businesses, which enhances their appeal."

"Mazars is renowned for its audit services that combine technical proficiency with personalized client care. Operating with a unique integrated approach, they provide holistic services that encompass audit, advisory, and consulting, making them a one-stop solution for clients. Their global presence combined with local expertise allows them to cater to diverse client requirements efficiently."

"RSM has built a strong reputation in London for its audit and assurance services, particularly within the entrepreneurial and mid-market sector. They adapt their services to meet the needs of dynamic businesses, employing a hands-on approach that ensures timely communication and personalized services. RSM's responsiveness and client-focused solutions solidify their position as a trusted advisor."

"Crowe combines in-depth sector knowledge with a keen understanding of regulatory changes, making them a reliable choice for audit services in London. Their agile approach allows them to adapt quickly to client needs and changes in the market, ensuring a tailored service experience. The firm's commitment to building strong relationships is reflected in their high client retention rates."