Anyone that still hasn't sent in their 2011/12 tax return online could be hit with more penalties from next month, HMRC has warned.

From 1 May, HMRC says it will charge a £10 daily penalty for each day an online return is late, up to a maximum of 90 days. This is in addition to the initial £100 late-filing penalty for missing the 31 January filing deadline.

For paper returns, daily penalties started on 1 February, as they were due by the earlier deadline of 31 October.

HMRC urges people not to send a paper return now 'as it will trigger an amount equal to, or close to, the maximum daily penalty charge of £900'.

And it warns that penalties of at least £300 (or 5% of the tax due, if it is more) will be issued for returns that are six and 12 months late.

Anyone who's received a late-filing penalty and hasn't yet sent a return, but thinks they don't need to be in Self Assessment, should call HMRC on 0845 900 0444. If HMRC agrees, the return and any penalty will be cancelled.