You must have registered with ISD and received your IRP card- if you have not registered you are not eligible for work.
Under the conditions of a student visa (stamp 2) you can work up to 20 hours a week during term time.
This includes while doing dissertation or waiting for results.
This is extended up to 40 hours a week during a holiday period, June to September inclusive and from 15 December to 15 January. For more info on this - click here.
Once you have received your results and successfully completed your programme you will be able to apply for a 1G (Grad Visa) More info on 1G Visa - available here.