Coffee Break Cryptic

28 April

Across

1 Prudence, maybe, is no credit (10)
7 Musical state (8)
8 Tiny bit in letter from Greece (4)
9 Nothing more than a distress signal, neither good nor bad (2-2)
10 Discipline little Charles at an early age (7)
12 Surrey town that is to inflict corporal punishment on school principal (11)
14 Old music maker is only after old wine (7)
16 Only fair (4)
19 Roman emperor confined in one room (4)
20 Bear load that could be delightful (8)
21 Boatmen transporting old signore (10)

Down

1 Subscription constraining king and noblemen (5)
2 Bird going to main Welsh port ... (7)
3 .. bird seen on board? (4)
4 Instructors going out to the races (8)
5 Doesn't include moist patch? (5)
6 Be there for a tiptop nurse (6)
11 Amount distributed in handouts (8)
12 Foliage goes away (6)
13 Strive to equal bird that's not on time (7)
15 Tokyo, strangely, is a city in Japan (5)
17 Drinks supplied after end of short stories (5)
18 Put out a container (4)