Cryptic crossword No 3,966

Across

1. They measure current attitudes, monitoring popular sentiments from the outset (4)
2. Normal diet that you'll get at the UN? (7,8)
3. Joke around with the odd bits of toast? That's an order! (6)
4. It's the devil in me - pub's closing too early! (8)
5. Manly actor wanting a L'Oreal make over for prestigious event (5,5,5)
6. City scoundrel blocks support for Head, mainly for minor misdemeanour (10)
7. What you might encounter at sea during era a historian recalled (4)
8. Big jobs for deputies (6,4)
9. Union ultimatum? (4,2,2,5,2)
10. American buffalo (two, large) in swamp (8)
11. Ruin opening gag after sacking a member of shoot (3,3)
12. The most well-known address in America? (5,2,3,5)

Down

1. Sculptor dealt with loon going crazy (9)
2. Croon over one extraordinarily large flower found in South America (7)
3. Abridged very long book for example (7)
4. Person once at peace intermittently follows the most extreme characters (5)
5. Fleet manager's Russian car holds edge when reversing (7)
6. Second year student's awful prose about man and his ancestors (9)
7. Fate of current artist supporting a particular way of working (5)
8. Give away or hire out underwear (3,4)
9. Invent a new piece of instrumentation for making serum (9)
10. A brief meeting packed with people being obdurate (7)
11. Sounds like she'd already left business and that's ideal mate! (2,5)
12. Drive away from refuse tip to hide (5)
13. Predator with each leg broken (5)
14. Drug baron charged with "shoddy stuff and nonsense" finally after disposing of old boy in Volvo? (6,3)