Conservative PM's beginning to expel foreign nationals (8)
I believe the answer is:
israelis
'foreign nationals' is the definition.
(people from Israel)
'conservative pm's beginning to expel' is the wordplay.
'conservative pm's' becomes 'Disraeli's' (19th-century prime minister Benjamin Disraeli).
'beginning to expel' means to remove the first letter (the letter at the beginning is expelled).
'disraelis' with its initial letter removed is 'ISRAELIS'.
(Other definitions for israelis that I've seen before include "They might live in 4 down" , "'They live in Tel Aviv, say (8)'" , "Nationality of citizens of Tel Aviv" , "Nationality of citizens of Jerusalem" , "They might live in Tel Aviv, say" .)