My friends were asked for proof they were registered in the country they got their degree from (not UK but sure will be the same), I head they just sent a certified copy of their current practising certificate.
Are practising certificates used in the UK? Back home we get a new one printed annually(from the start of pre-reg), and are theoretically supposed to display a current (i.e not expired yet) one in the premises you are practising in. Since starting pre-reg here I have not had any papers apart from the work book. Still have my old pre reg practising certificate, it has a paragraph explaining what a pre-reg must be under supervision for a continuous period etc.
A quick look on
NABP <> National Association of Boards of Pharmacy (chose Examination Programs then FGPEE/FGPEC) seems to indicate that registration in the country you trained is a a requirement but perhaps you can contact them and find out if they will waive in for you.
If I recall the procedure is
1. Get academic equivalence (fifth year is pre-reg) (cost US$85 compared to £685 RPSGB)
2. Apply for and pass FGPEE to get a FGPEC (cost around US$700 plus transport etc, UK OSPAP £6500++ plus living and transport)
3. Internship and state licensing exam ( varies: equivilent of UK pre-reg)
All this if you already have a work permit. Since it is so much cheaper if residency works out most foreigh phamacists would opt for states over UK. Thats also why you see very few US registered pharmacists coming to the UK. I canm't understand why the RPSGB wants somebody educated up to a doctrate level to upgrade their qualifications to a master's level qualification.