The highly regarded Institute of Fiscal Studies is a wealth of information:-

Pressures on public sector pay | Institute for Fiscal Studies

“The public sector employs 5.9 million people in the UK, at an annual cost of £270 billion in 2023–24 (including salaries, employer pension contributions and employer National Insurance contributions) – 10% of national income and 22% of total UK government spending. The employment, pay and productivity of these employees are therefore an important determinant of the material standard of living of millions of families, as well as a crucial input into the provision of public services. Public sector pay growth is an important pressure on public spending.”