For personal reasons im going to quit my PhD. I do not intend to give notice or a reason to my supervisor or university. Will I have to pay back my bursary? Ive been recieving £875 per month since october. Thanks

You should only have to pay back money paid to you in advance. eg if you have already been paid for February you will have to return this money. You may need to check the terms of your grant though, as (although we are not aware of any) some funding bodies may apply other conditions which could include the repayment of course fees paid in advance.

Whilst your reasons for leaving may be private, you should consider giving some notice to your supervisor (you do not have to tell him/her why you are giving up). You will certainly need to give notice to your grant awarding body and it is likely that you will need to do this in conjunction with your supervisor. Even if your relationship with your supervisor is a bad, leaving unannounced will cause problems lots of other people who have nothing to do with your reasons for leaving and you should show them some consideration.

Also, you're damn rude to walk out without "notice or reason". Disgusting.

thanks. what notice should i give? what is the point in comming in to research during my notice period when i'll be leaving? Would it be enough to write to my awarding body and supervisor telling them i dont intend to continue?

You may find that you are contractually obliged to work a period of notice, check your contract. The 'point' is that it is a courtesy to your supervisor and keeps the work going while he/she considers your replacement. However, you may find that they are a willing to let you stop without working a period of notice. Your best bet is to sit down with your supervisor and discuss your intentions and hopefully, it can all be resolved amicably.

You are unlikely to be asked to serve much of a notice period. Whatever the validity of your reasons for leaving, you are inevitably letting some people down. It is courteous to go in and see what loose ends they would like you to tie up before you leave.