You should have already received an automatic £100 initial filing penalty. This is payable; regardless of whether you had no tax outstanding or you were due a refund.
However, from the 1st May 2014, the daily penalties of £10 per day will begin, but these will be capped at £900.
I would encourage you to file your return as soon as possible and ideally, no later than the 1st August 2014- when a further penalty of £300 or 5% of the tax due (whichever is higher) will be added to your existing penalties. Further penalties will be triggered if the return is over 12 months late.
Please note, the dates referred to are based on the online filing of the return. If, when you file the return, you use a paper version you will face more significant penalties as paper tax returns should have been filed by 31st October 2013.
If you are struggling to keep on top of your taxation affairs, your local TaxAssist Accountant could prepare your return for you. Please feel free to contact us for more information or your free initial consultation.