Tomorrow, (January 31) those who are self-employed will need to complete their self-assessment tax return to avoid missing the deadline. New research from Handelsbanken Wealth & Asset Management has found that a total of more than 600,000 self-employed people think they will miss the deadline.

Jim Harra, chief executive of HMRC's comments on careless tax returns last week, said: "If your error was as a result of carelessness, then legislation says that a penalty could apply in those circumstances".

The research from Handelsbanken Wealth & Asset Management found that:

• Young men aged 18-34 are most likely to believe they will miss the self-assessment tax returns deadline, with 13% of them fearing they won't respond in time
• Half (50%) of working adults say they are a PAYE employee with no additional income while, more than a quarter (28%) are retired, meaning that nearly a third (29%) – 9.4 million people –are self-employed in some capacity
• Men (25%) are more likely than women (16%) to have an income stream from self-employment
• While younger adults aged between 18 and 34 are much more likely to be self-employed at 40%, compared with older age groups
• Just 20% of those aged 35 to 54 are self-employed to some extent, and only 10% of those aged 55-plus have additional self-employed income