How many UK prime ministers has there been since 1933?

There has been a total of 18 UK Prime Ministers since 1933. They are:

1. Ramsay MacDonald
2. Stanley Baldwin
3. Neville Chamberlain
4. Winston Churchill
5. Clement Attlee
6. Winston Churchill (he was re-elected)
7. Sir Anthony Eden
8. Harold Macmillan
9. Sir Alec Douglas-Home
10. Harold Wilson
11. Edward Heath
12. Harold Wilson (he was re-elected)
13. James Callaghan
14. Margaret Thatcher
15. John Major
16. Tony Blair
17. Gordon Brown
18. David Cameron