November 1 2012.

If you haven't yet sent in your 2011/12 tax return, you must send it online if you want to avoid a penalty, as the 31 October deadline for paper returns has now passed.
Paper tax returns received on or after 1 November will result in a £100 penalty - even if there is no tax to pay or the tax due is paid on time. The longer you delay, the more you'll have to pay, as there are further late-filing penalties after three, six and twelve months.

Your online tax return must reach HM Revenue & Customs (HMRC) by 31 January 2013. If you haven't sent an online tax return before, make sure you register for HMRC Online Services in good time. This will allow HMRC time to send you your Activation Code. Registering for HMRC Online Services is simple - just go to

It's important to remember that, if you do send a paper return after the 31 October deadline, you cannot avoid the £100 penalty by subsequently filing online.

For general help and advice on completing a return, visit or call the Self Assessment helpline on 0845 9000 444.