Over three decades Peter has appeared before parliamentary hearings across Europe, most frequently before the European Parliament. He has presented audit findings and answered questions from elected representatives on subjects ranging from research spending and animal welfare to digitisation, better regulation, agriculture and climate policy. He has also appeared before parliamentary committees in Ireland and Croatia, and before numerous formations of the Council of the European Union.

In 2021 Peter was one of a small group of representatives of the Supreme Audit Institution community to present at COP26 in Glasgow, drawing on work undertaken under his leadership at the European Court of Auditors on climate action, agriculture, emissions trading and energy efficiency. He drew on this body of work when he authored the UNDP Good Practice Guide on Climate Change Audit – Making a Difference – in 2026.

Peter has contributed to both the international Supreme Audit Institution community and the professional accountancy community. Through INTOSAI and its regional organisations, his work has included developing guidance, chairing and moderating international discussions, serving on expert panels, and judging the INTOSAI WGEA visualisation awards. He has sought to strengthen public decision-making by promoting performance audit, improving the communication of audit findings, and encouraging the use of audit evidence to support better governance, climate action and public financial management.

Within the professional accountancy community, Peter is a member of both CIPFA and CIMA, serves on CIPFA's Council, chairs Accountancy Europe's Public Sector Group, has spoken on several occasions at Public Finance Live and ACCA events, and has contributed articles to the journals, publications and websites of IFAC and ICAEW.

At the OECD, Peter led work on public sector audit within the Public Management and Budgeting Division. He played a key role in establishing the OECD network of Auditors General and Heads of Supreme Audit Institutions and continues to contribute to its activities.

Peter's work has focused on how governments and public sector bodies make decisions, how they account for their activities and how audit and financial reporting can improve governance. Following work to reform accounting in humanitarian operations in Ethiopia and experience in the health and water sectors in Bolivia during the 1990s, he contributed to recommendations on the adoption of accrual accounting by the European Commission. He was invited to speak on these themes at the inaugural EPSAS conference in 2013 and the Global Leadership Summit in Los Angeles in 2016.

Peter led pioneering work applying the IFAC/CIPFA Good Governance framework to the European Commission. This led to invitations to present on the findings and approach at the CIPFA International Conference in 2016, and in New Delhi in 2017, and to contribute articles to the IFAC Knowledge Gateway and the journal of the Pakistan Institute of Public Finance Accountants (PIPFA). He has frequently spoken at national and international events organised by government accountants in Latin America.

These themes come together in Making a Difference, which argues that audit achieves its greatest impact on the quality of public decision-making through better governance, stronger incentives and more useful information. More recently—notably in the Western Balkans—he has further emphasised the links between fiscal and environmental sustainability and the need for accountants and auditors to address emerging risks.