cambio de trabajo en UK

Depende, si tu visa de trabajo fue tramitada por tu actual empleador, dice la ley que debes trabajar con ellos por 4 años, despues de ese tiempo estaras habilitado para aplicar para la residencia, con lo cual tendrias la posibilidad de cambiar de trabajo cuando quieras.
Depende te digo, porque no se como tramitaste tu woking visa.

Saludos

If the employment for which the work permit was issued ceases prematurely, or a person admitted as a work permit holder does not take up the employment for which the work permit was issued, the person may be deemed to no longer meet the requirement of the Immigration Rules under which he/she was admitted and action may be taken to curtail their stay, and the stay of any dependants, in the United Kingdom.

Where employment ceases, the conditions attached to any remaining leave to remain will not confer permission to remain for the purpose of seeking alternative employment. If the person has found alternative employment, we may consider a work permit application from the new employer but may not grant further leave to remain in the UK unless it is satisfied that the individual has taken steps to find new employment as quickly as possible.

fuente :
[url]http://www.workingintheuk.gov.uk/working_in_the_uk/en/homepage/work_permits/applying_for_a_work/business_and_commercial/new7.html?[/url]