UK ESG reporting requirements in 2026: what mid-sized companies must disclose

The UK disclosure landscape has tightened considerably over the past three years. Large listed companies have reported under the Taskforce for Climate-related Financial Disclosures since 2022, and the Transition Plan Taskforce framework has become the reference point for credible net zero planning. For companies outside the listed perimeter the pressure arrives differently: through lender covenants, through public procurement, and through customers who now pass their own reporting obligations down the supply chain.

In practice most mid-sized UK companies now need to answer four questions. What is our Scope 1 and Scope 2 footprint, and is it assured? What are our material Scope 3 categories, and how are they estimated? What climate risk sits in our operations and supply chain, and who owns it internally? And what is our transition plan, with dates and capital attached?

Limited assurance is the next threshold. Banks and large customers increasingly ask for an independent opinion on reported emissions, and the requirements of ISAE 3000 (Revised) mirror the disciplines of an ISO management system: documented methodology, retained evidence, defined boundaries and management review.

The practical route is rarely a single report. It is a data system. Emissions factors, activity data, site boundaries and organisational changes must be traceable year on year, otherwise the second report costs more than the first and the numbers move without explanation.

Our advice to UK boards is to build the reporting process as a management system first, using ISO 14064-1 for quantification and ISO 14001 for environmental governance, and to treat the published report as an output of that system rather than a project.