Since the introduction of the Tier 4 student visa on 31 March 2009, both students and the educational institution sponsoring them have been required by the Home Office to adhere to certain responsibilities.
The main conditions of your Tier 4 visa whilst you are studying at Imperial College London can be located here: visa responsibilities and are to assist you in maintaining an excellent immigration record.
Further information about visas is available on the International Student Support webpages.