OECD: UK tax level reaches record high The UK's tax level has reached its highest rate on record, according to new data from the Organisation for Economic Co-operation and Development (OECD). The total tax-to-GDP ratio hit 35.3% for the 2022/23 financial year, representing a 0.9 percentage point increase from the previous year. The UK has the 16th highest rate of 38 OECD countries and is 1.3 percentage points above the group’s average of 34% in regard to tax competitiveness.