You will find all the information on the Inland Revenue website:
<http://www.inlandrevenue.gov.uk/nic/ynino.htm>

Basically, you will have to contact them. If you don't know which office to go to, you can contact the National Insurance / Registrations Helpline:
Telephone (UK): 0845 91 57006 or 0845 91 55670
Open Monday to Friday 8:30am to 4.30pm.

For London you will find other addresses on our page:
Work/National Insurance Number

 

Please let me know how i can go about getting my NI number? I am told i cannot obtain this number unless i am employed, then prospective employers tell me they cannot hire me unless i have an NI number, what do i do? I need to find a job before my NI number will be issued to me, but there again no one will hire me without my NI number. Please reply to me at niquiuk@hotmail.com and let me know what i am supposed to do because i am over on a 2year working holiday and this is keeping me from finding a job. Who do i contact?

 

most of the information you require is there:

National Insurance Number

and any employer's accountant should know about temporary number.

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