Income tax is a tax levied on the income of individuals, partnerships, and trusts. It is collected by HM Revenue and Customs (HMRC).

The amount of income tax paid by an individual in the UK depends on their income, and is calculated using a progressive tax system. This means that the more a person earns, the higher the percentage of their income they will pay in tax.

As of the tax year 2022/23, individuals in the UK are entitled to a tax-free Personal Allowance of £12,570. This means that the first £12,570 of their income is not subject to income tax. The basic rate of income tax in the UK is 20%, which is applied to income above the Personal Allowance and up to £50,270. Income above this threshold is subject to higher tax rates of 40% and 45%, depending on the amount of income earned.

Employers in the UK are required to deduct income tax from their employees' pay and remit it to HMRC on their behalf. Self-employed individuals are responsible for paying their own income tax directly to HMRC.

Individuals in the UK are required to file a tax return with HMRC each year if they have income that is not taxed at source, such as income from self-employment, rental income, or investment income. The deadline for filing a tax return online is usually 31 January following the end of the tax year.