Overseas Students & Vacation work
The position is fairly straightforward with respect to Overseas students and vacation work. If you are registered on a U K course you have the right to work in the UK without a work permit. Sometimes the employers are confused as a small number assume that the rules are the same as for Graduates, however, they are not.
However please note that if you are a Romanian or Bulgarian student you will need a Registration Certificate. See the following link Border Control Regulations
Also students may also be confused by those employers who make eligibility to work full time in the UK ON GRADUATION as one of the criteria for for vacation work jobs. Effectively this means they are looking to recruit potential future full time employees via vacation work opportunities so they want to make sure that if they like you, there are no barriers to hiring you when you COMPLETE your course.
Work Permit regulations for Undergraduate Vacation Work
If any employer has any doubts, you should refer them to the H M G Home Office U K Border Agency web site which clarifies the issues with regard to Work Permits & Overseas Students.
Work Permit regulations for Full Time Work on Graduation
Re the Graduate market, this is infinitely more complicated and forever changing, Up until recently ( May 2008) students could work in the UK for 12 months without a work permit. he scheme is called the International Graduates Scheme ( I G S ) . However this scheme is now closed and has been replaced by Post-study workers which allows students who have been registered with a UK University to work in the UK for 24 months. I have a document from Careers Service which summarises the main points Click to read it.
Please note that the Government regulations re Work Permits and employment are subject to frequent fluctuation and change so it pays to check the site regularly.