Thalia joined Opus at the beginning of 2019. Since joining the firm, Thalia has advised clients and gained transactional experience in the Energy Transition and Climate Change, Financial Services, Consumer and Retail and Healthcare sectors.

She previously spent over 3 years at PwC in the London Region Assurance practice, where she qualified as a Chartered Accountant, focusing on mid-market private and public listed companies across a wide range of sectors.

Thalia holds a BA in French from the University of Oxford and is a member of the ICAEW.

Charles Lesser joined Opus in July 2025. He advises corporates and institutional investors on M&A and equity investment in energy system flexibility and renewables generation across Europe. His clients include Lightsource BP, SSE, Ford, BMW, Low Carbon, Next Energy Capital, Mercuria, Sandbrook Capital, Antin, FRV, BayWa, General Motors, Fluence and Umicore.

He is a frequent writer and speaker on evolutions in the battery storage industries, and shifts in the IPP and solar business models. He was formerly UK CEO and global head of Transactions at Apricum, and head of European Energy investment banking at Macquarie. Like many Opus founders, his ‘client-first’ values come starting his early career at SG Warburg, the foundation of UBS Investment Bank.

He also sits on the Board of Speakers Trust, an educational charity and holds an MA from the University of Cambridge, UK.

John co-heads Opus’s market leading Energy Transition & Climate Change team advising a wide range of clients on renewable energy, renewable chemicals and materials, sustainable transport, and resource efficiency. Recent transactions including capital raising for Eelpower to fund its grid connected battery storage roll out, the sale by Ecotricity of its Electric Highway EV charging business to GRIDSERVE, the sale of DEXMA, a Spanish energy management software business to Nemetschek Group, the sale of Pensions Infrastructure Platform to Foresight, equity fund raising for Carbon Clean, and the sale of Baringa’s Climate Scenario Model to BlackRock. Current areas of focus include electric mobility, grid flexibility, hydrogen and smart buildings.

Prior to joining Opus in 2008, John spent 20 years at SG Warburg and then UBS Investment Bank in London and New York focusing on cross-border M&A, and latterly ran the corporate finance advisory business of UBS Wealth Management in London.

He has a BSc (Econ) degree from University College London and is a member of the ICAEW.

Nigel has been a partner at Opus since its inception in 2006. Nigel has clients across a broad range of sectors and specialises in advice to entrepreneur, family and trust owned businesses. Areas of sector focus include the Built Environment; B2B consulting and tech-enabled business services; and media and events.

Recent assignments have included advice on: the financing of a modular housing manufacturer; the sale of an international B2B events business; the sale of a private members club; and the sale of a financial services software and services provider.

Nigel joined SG Warburg in 1983 and in 1997 was recruited as Head of Corporate Finance at Enskilda Securities in London. Nigel has a degree in Economics from Cambridge University and is a member of the ICAEW.

Joel joined Opus in 2024 and provides deal support across both M&A and fundraise transactions.

He has experience across a range of Energy & Sustainability sub-sectors, including BESS, software and e-mobility. Joel has particular expertise in financial modelling and the preparation of transaction materials.

He began his investment banking career at Opus following a successful placement year with the firm in 2023. Joel holds a degree in Economics from Durham University.

Michael joined Opus in 2017.

Michael has extensive experience in both M&A and capital raising across various Energy & Sustainability sub-sectors, including battery energy storage, controlled environment agriculture, circular economy manufacturing, industry decarbonisation, and energy management software.

Recent transactions include advising an infrastructure fund on its investment into a vertical farming platform, raising growth equity and construction debt for a circular economy manufacturing business, and several battery energy storage fundraises and asset sales.

Prior to joining Opus, Michael worked for ICA Partners in Australia, advising clients on infrastructure, energy and renewables M&A and project financing. Michael holds a Bachelor of Economics with First Class Honours from the University of Sydney.

Richard has been a partner at Opus since 2011 and co-leads the Energy Transition & Climate Change team. Richard is primarily focused on the energy and infrastructure sectors, and has a particular expertise in M&A, project finance and fund-raising for energy technology companies. Recent assignments have included advice to a renewable energy project developer, raising funds for a new power station, and also advice to an electricity storage technology development company on successive fund-raisings.

As well as his work with Opus, Richard is on the Boards of The Renewables Infrastructure Group (TRIG), Heathrow Southern Railway Limited, and the Leeds International Piano Competition.

Richard joined Kleinwort Benson in 1981 whence he was seconded to be Deputy Director General of OFGEM from 1999-2001. Following a brief stint as head of Utilities and Infrastructure for Europe at Goldman Sachs, he led the energy and infrastructure team at Greenhill & Co. He was educated at Winchester College and New College, Oxford (Classics). He is an honorary fellow of Ripon College, Cuddesdon.

Dilesh joined Opus in 2021. He has a strong background in financial modelling, working on transactions across a range of sectors including Energy Transition & Climate Change, TMT, and The Built Environment.

Prior to joining Opus, Dilesh was most recently part of the Transaction Modelling team within EY London, focusing on developing complex financial models to support strategic investment decisions. He also worked as part of the Financial Reporting team at Shell Trading, with a focus on LNG Freight and Shipping.

Dilesh has a BSc degree in Economics from Brunel University and is also a Chartered Financial Analyst (CFA).

Tom joined Opus at the beginning of 2021. Prior to joining Opus, Tom spent over five years at PwC in the Audit and Corporate Finance practices, where he qualified as a Chartered Accountant.

Tom has over two years M&A advisory experience for clients across a range of sectors. Tom holds a BEng in Engineering from the University of Sheffield and is a member of the ICAEW.

Stuart joined Opus in 2008 and co-heads the team.

Stuart has broad experience advising across Energy & Sustainability sub-sectors, spanning infrastructure, services and technology clients. He has particular expertise in M&A and fundraising for energy services, smart grids, heat decarbonisation, sustainable transport and resource efficiency companies.

Recent transactions have included advising a PE fund on its investment into a grid services company, advising on the sale of a specialist industrial waste services company and advising an infrastructure fund on its investment into a vertical farming platform.

Stuart started his investment banking career at UBS in 2004. He has a degree in Chinese from Durham University.