Most people living in the UK are required to pay tax on their income. Your Income can be from business profits trading as sole traders, partnerships, salaries, wages, tips, commission, property rent, and dividends and so on.
Generally you must pay your income tax in three installments: first payment on 31 January and the next payment on 31 July and with the final payment on 31 January on the following year.
You must file your self assessment return to HMRC before or on 31 January. Any tax overpaid for the accounting year will be refunded to you by HMRC.
There are interest penalty on unpaid tax and fine if you file incorrect self assessment return.