2408: End of the line

Unclued lights name a man born on 18 May; his position; his son; and (singly or correctly paired, two of two words) some of his predecessors. One unclued light does double duty.
 

Across

1    Listless and irrational in a sort of pit (6)
10    Played in new group, keeping time with skill (7)
11    Furious as flower’s name concealed (7)
14    Set of eight, not restrained at all in Alloa (6)
17    Unwilling to move through container terminal (5)
18    Side channel’s singular state (3)
24    I point: see snake, minus tail (8, two words)
25    Milton’s drain of extremely small benefit (5)
26    Laughs loudly; that’s annoying north of the border (5)
28    Remainers are fine in the German section (8)
31    Don’s wife disguised seaweed (7)
34    I came in to wonderful cry of approval, a fixture in the room (9)
36    In excessive quantity, drink just opened left over (3)
38    Scratch round number (5)
39    Having eaten out, collected female to drop off (6)
40    Rank wild cat heartless (4)
41    Suddenly a bill of small value (7, three words)
42    Cutting cake, one line twisted (7)
44    First meaning to be martial arts teacher? (6)
 

Down

1    Spring celebration always suppressed by Chinese authorities (6)
2    Toothy student demolishes good round Stilton (12)
4    Tyrant taking time for large pill (6)
5    Hawk once turning up for example at noon (4)
7    Where growth is forced, hold half bad debts (7)
8    Introduce Romance language round Spain (6, two words)
9    Caught in group in suspended trap (8, two words)
13    Takes down soldiers’ trousers (7)
15    From the highlands, ornately dressed (8)
16    Sea creature that circles the planet? (12, two words)
19    Buds that develop that birds may take (8, two words)
22    Isle not fancy; a superlative unnecessary? (7)
27    Shrew, very new at food counter (7)
29    Court a piece of fluff, maybe a tawny creature (7, two words)
30    Sailor catches big bird: it perforates (6)
32    Game opponents in dreadful want (6)
37    Love piece of Morse and its meaning (4)
 
A first prize of £30 for the first correct solution opened on 3 June. There are two runners-up prizes of £20. (UK solvers can choose to receive the latest edition of the Chambers dictionary instead of cash — ring the word ‘dictionary’.) Entries to: Crossword 2408, The Spectator, 22 Old Queen Street, London SW1H 9HP. Please allow six weeks for prize delivery.