The R&D tax credit in the UK is a government incentive designed to encourage innovation and investment in research and development. Businesses can claim tax relief on eligible R&D costs, which can either reduce their tax liability or, in some cases, result in a cash payment. There are two main schemes: the Small and Medium-sized Enterprises (SME) scheme and the Research and Development Expenditure Credit (RDEC) scheme for larger companies. The amount of relief available depends on the company size, the scheme, and the qualifying R&D costs incurred.