Last year, the UK government raised £1.1 trillion from taxes but spent £1.22 trillion. The taxes mainly come from income tax, national insurance, VAT, and corporation tax. Most of the spending goes to health, pensions, social security, education, and defence.
The difference between what the government receives and what it spends is the surplus or the deficit. In 2024, the UK spent more than it received, and so there was a £122 billion deficit. In Switzerland, the government spent less than it received and had a modest budget surplus.
If a government has deficits year after year, they soon add up. The UK now has a national debt of £2.8 trillion, which is often shown as a percentage of the economy. The UK GDP was roughly £2.54 trillion last year, so the debt has grown to a size that is slightly larger than the economy.