If the you do not need UK Entry Clearance then you can fly to the UK on the day the Work Permit is approved and printed. If an application goes smoothly, the Work Permit will usually be printed within 3-4 weeks of making the application.
During times of peak demand and during holiday periods (in particular late July to the end of September, and mid December to mid January) processing times often become slightly extended.
Because of Security clearance procedures, applications take a little longer for Russian nationals, and can take a lot longer for nationals of North Korea, Libya, Iraq, and China (PRC)
If the you needs entry clearance, entry to the UK will usually take c3 weeks from the printing of the Work Permit. For details on obtaining entry clearance, please Click Here.