I'm working in the UK under a Tier 2 visa. I've been offered a better job, and already the new employer provided a certificate of sponsorship. However they need a quick start, and the star date (also in the certificate) is 9th September. Even if I complete the application today or tomorrow, I need to give a month's notice at the current job, so can't wait to have an answer before resigning. My questions are: 1) In your experience, how long does it take to get a new BRP when changing Tier 2 Sponsors? Would you recommend paying the premium fare, to get a result before next month? 2) In your experience, how likely is it to have a switch of sponsors refused? I would be moving into a shortage occupation job, in case that makes any difference. 3) If for any reason it all goes wrong and the switch of sponsors is refused, what are my options? Is it possible to "un-resign"? Would I have to leave the country immediately? Thanks in advance.