It's pretty difficult. There are only 20k slots released every year and you have to prove that nobody in the UK and then the greater EU can do the job.
I see, 20K is pretty low. But regarding proving - I guess you'll only need to prove only within those who applied to your particular job posting (in case you want to pick "outsider" over UK citizen).
And this procedure is a peace of cake for financial organizations/banks, as it seems.
