All outstanding 2010/11 Self Assessment returns must be sent online to HMRC by 31 January 2012. If you send your return after that date, you will receive a £100 penalty – even if you have no tax to pay or you pay your tax on time.

The longer you delay, the more you'll have to pay. If your tax return is three months late, you'll have to pay a penalty for each additional day it is late. If it's six months late, you'll have to pay a further penalty and another, final penalty, if it's 12 months late. Together these could add up to a penalty of £1,600 or more.

The week running up to the 31 January deadline is always a busy time for HMRC’s online systems. As the deadline draws nearer, the number of people sending their return increases. Last year, this culminated in more than 570,000 people filing online on the 31 January – the busiest day of the 2009/10 filing calendar.

While HMRC’s systems are able to cope with these large volumes of online returns, inevitably, at busier periods, it may take people a little longer to complete their online return. With this in mind, it makes sense to get that online return to HMRC as soon as possible.

For help and advice on completing a return, you can visit www.hmrc.gov.uk/onlinereturn or call the Self Assessment helpline on 0845 9000 444.

And don’t forget, 31 January 2012 is also the deadline for paying any tax you owe for the 2010/11 tax year.

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