I suspect it’s quite a clever move. The UK and EU medical agencies use the same standards. They are getting the same data, they will be following the same procedures. That means outcomes should be similar.the U.K. has been emergency approval, the EU is hoping to grand full.
the U.K. is taking a major risk.... hopefully it pays off
If the EMA finds something serious enough to stop the vaccine, then the UK will have only exposed a relative small number of people, meaning minimal harm.
If the EMA finds nothing serious enough to stop the vaccine and authorise it’s use, then the UK can do the same, whilst being 3 to 4 weeks ahead in the vaccination program.