Cryptic crossword No 2,761

Across

1. Informer backs worker you said left a small organism with many black legs (9)
2. Scribbled hint to spy — His looks might seduce you (9)
3. Desert tribe scramble to get on (3,4)
4. Told off! Earliest of radishes gobbled in garden plot (7)
5. Consumed within measure, and in its entirety (5)
6. River rises, losing banks and direction, exposing fibrous crop (4)
7. Name most of means needy people preferred to recompense Charlie (10)
8. Entertainer, having lost heart then lost head, is one at a loose end (5)
9. Book said to be wholly written by hand now available in printed edition (9)
10. Island besieged by British warships, first of destroyers outside (4)
11. Building to some extent protected if I certify (7)
12. Learner backs up endless hill, hellish giving way to first of potholes (5)
13. Measuring system bewildered tyro head of work crew (4,6)
14. Legislate part of what can ensue in retrospect (5)
15. Great Lakes fishing-boat winding in gear now (9)
16. Titular head of nonconformists, in a final bit of betrayal, accepts an award (7)

Down

1. London arose far off in pursuit of unfindable things (2,1,5,6)
2. Care is demanded here — Runs up, beginning to end English hollow reply (7)
3. Narrow-minded I note, turning us closer to liberal fringes of affair (7)
4. Write respectful form of address about one in receipt of assistance (9)
5. Point indicates possibility in unlimited degree (5)
6. Minute rag can carry written messages (4-5)
7. Choose skipping half of lectures after first of exams (5)
8. Foresee colour infiltrating half-concealed pictures (7)
9. World magnetic property about turns, spins around overhead (7)
10. Group leader's not half tetchy! (5)
11. Far-left worker admits — To importune for payment? Without purpose! (9)
12. Unemployed go in force to open business competition (4,10)
13. Exhausting accommodating an upset unmarried mother! It's no laughing matter (9)
14. Left me upset with respect to colour (5)