Part time freelancer in the uk do i have to pay taxes and how ?

Do you work fulltime/part time currently?

You need to tell HMRC as soon as you become self employed, but you wont pay tax till your earnings have hit over the limits I put in the 1st link.

If you delay telling them, you may get a fine.

No problem, just keep tabs on all that you spend, it all adds up for example tree house payments over a year, that's £50 saved on tax right there, training relating to the business is tax deductible.

Also, any work you do now would fall into the 2014/15 Tax year.

This means the tax due would be calculated for the year to 5 April 2015, the tax would need to be paid by 31 January 2016 and the tax return would need to be submitted by this date.

This is a fairly long time, and what tom said is mostly correct, Under UK Regulations payments on account are not due where the relevant amount is less than:

a fixed amount of £1,000, or the proportion the relevant amount bears to the assessed amount is less than 1 to 5.

So if more than 80% of the assessed tax is met by income tax deducted at source no payments on account are required.

Given the above, if you make profit of >£5,000 it is likely you will need to also pay payments on account. These are half of the currrent assessment each, one falling on 31 January 2016 (same time as actual tax) of 50% and the other 50% on 31 July 2016.

When your tax for the following year is calculated, the payments on account are deducted from tax due, reducing your tax payable on 31 January the next year.

If it was a one-off and you do not expect to be paying any tax the following year (or significantly less tax) you can call HMRC and have the payments on accounts reduced or removed.

I would have two folders on your PC(or actual folders) one for invoices(income) and one for expenses, this would be the easiest way to get started. Also, I would recommend wave accounting app online, it is free and I use it often!

Hopefully this wasn't too much of an information overload. Let me know if you have any other questions.

My apologies, my answer was in addition to what was said above. I will correct my answer.

Yes your personal allowance for 2014/15 is £10,000, but if you do any other paid work or have another part time job this will reduce it too.

To sum it up, make profit (income less allowed expenses) of >£10k and you will pay tax, make over £15k profit and you will have to pay tax AND payments on account.