1: Mathematician's analysis of former Vice President's movements? (9)
2: Nude redhead receiving backward glance is one serving drinks (9)
3: Cooped up in Essex: pelicans, it would turn out (5)
4: Rejecting crew's work on board, you rest at the stern (8,3)
5: I'm great novel detective (7)
6: Six points making a case for one in good shape (5)
7: Gloomy semi-dull firmament (5)
9: Hoarded tiny bits of dryness (11)
12: Our neighbour recorded singles in the sub-continent (9)
13: Form of address valued for the auditor taken unawares (9)
15: There is a Santa, perhaps (7)
17: Probed announcer's self-esteem (5)
18: Nothing, nothing in shape (5)
19: Boxer Max returned, holding heroin, for treatment (5)