according to home office rules
you can work only on temporary contract part time. Not acceptable if u work permanent contract part time work , only temporary contract part time!!
below is UKBA reply to me for my question same as yours for work
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Thank you for yor enquiry.
Please accept my sincere apologies for the delay in responding to your enquiry.
Unless their visa states otherwise, a person who is aged 16 or over, and holds valid leave to enter or remain as a student or under Points Based System Tier 4, for 6 months or more, may undertake employment for:
* 20 hours per week during term time; and
* Full time during vacation periods.
A student must not engage in business, self-employment or the provision of services as a professional sports person or entertainer. A student is not permitted to pursue a career by filling a permanent full-time vacancy.
You can continue working full time when your studies are completed for a period of four months or until your visa expires, whichever is sooner, whilst waiting for your examination results, prior to attending your graduation ceremony or before commencement of your new course.
For further clarification and guidance regarding your enquiry, pleas click onto the following link:
http://www.ukba.homeoffice.gov.uk/studyi...
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Hope this will help