1 Fourth child of the PM (3,5)
5 Anglian kingdom of Central England founded in the 6th century (6)
8 Foul-smelling fruit of SE Asia. (6)
9 Welsh singer who first hit the top with It's Not Unusual in 1965 (3,5)
10 Bronze-like lustre in certain minerals; Friedrich von ---, German poet (8)
11 Young nobleman attendant on a knight (6)
12 BBC station broadcasting light entertainment and music 24 hours a day (5,3)
13 Belgian airline (6)
15 A swamp, bog or marsh in Canada (6)
18 Capital of Uzbekistan (8)
20 The immature free-living form of most invertebrates and amphibians and fish (6)
21 Five-toed pachyderm (8)
23 An organic compound with similar molecular structure to another but containing different atoms of the same valency (8)
24 Covering of polar regions (3-3)
25 --- O'Connor, Irish singer whose first number 1 was Nothing Compares 2 U (6)
26 Relating to fish (8)

1 Puts on board (5)
2 Jurisdiction of a bailiff (9)
3 Moulding in the form of a ring at top of a column (7)
4 1983 Star Wars sequel (6,2,3,4)
5 Imitation or representation in art (7)
6 Voltaire's 1759 novel (7)
7 Batsman who scored 124 not out in the First Test against Zimbabwe, 2000 (1,1,7)
12 Battle in which Marlborough was victorious, 1706 (9)
14 A gratuity or tip in various Eastern and African countries (9)
16/17 Actor who died in Aylesbury, Bucks recently at the age of 96. (3,4,7)
19 Scandinavian language (7)
22 Theme (5)