Cryptic across
5 Quickly student is immersed in the sort that’s undesirable around here (6)
7 Relax and breeze past union extremists (6)
9 Not very sophisticated this lot, in this spiel riotously... (11)
10 ...announcing (states the old queen), an artist (7)
11 Psalmist, in part, was a phoney (5)
13 Verges on one preposition containing another? (5)
15 Angel, one in Britain to rile violently against (7)
18 The emperor is unremitting in the East (11)
19 Zoroastrian’s view on equality (6)
20 Name a painter going somewhere in Japan (6)