Although you have until 31 January after the end of the tax year to file your Tax Return, if you file it online by 30 December and the amount of tax that you owe is less than £3,000, you can have the tax you owe collected through your PAYE code, rather than having to pay it in one go by 31 January.

This has considerable cash-flow advantages.

Example:

Adam files his Tax Return online on 15 December. He pays tax at 40%. He owes tax on income of£1,800 and chooses to have the tax collected through his PAYE code. This delays payment, spreading it throughout the following tax year and saving him from having to make a payment of£720 (£1,800 @ 40%) by 31 January.