Cryptic crossword No 3,144

Across

1. Time to cut a firm onion elaborately showing intelligence (11)
2. Leaders of foreign lands support retreating vessels collectively (5)
3. Relatively expensive ship bounces around, to be more precise (8)
4. Worshipper, "straightened out", backsliding after leaving court (7)
5. Wealth of stories attached to the French island's mysterious rock (7)
6. Sloppy exhausted politician taking test reversed into sign (7)
7. Besieged by taunts, rocker Scott shreds (7)
8. By virtue of expected protocol, at its heart (3,2)
9. Fellate bananas for promotional material (7)
10. Save energy following dash to stop trade (7)
11. Most outlandish enthusiasm outside of unconfined mania (7)
12. Orchestra cheapskate guards pipe (7)
13. Arouse us devilishly, philosopher (8)

Down

1. Trent and Clyde perhaps getting just deserts? (7)
2. Japanese class sampling Georgia rum assuredly tipped (7)
3. Fight against drug reportedly becomes jaded and flat? These could help (5,5)
4. A challenging experience regarding Chambers? (6)
5. Fools slide uncontrollably when cycling (4)
6. Out to lunch or dinner, say, taking in books (6)
7. Pronounced noses can be first-rate (5)
8. Vegetable to sink in hole (6)
9. "A lime!" - distraught message (5)
10. At first found it difficult delivering light yonder...awkward! (6)
11. Strike gold in Welsh city (6)
12. Partners in deception survive cab rides ignoring odds (6)
13. How to make Brain of Britain cease (5,2,3)
14. Essentially watery trip royal's making to find Eastern cooking method (8)
15. Reflecting on crazed haters: "It's salty in Europe" (5,3)
16. Road without banks becomes one with many branches? (4)