Ten unclued lights comprise a septet with a common theme.

Across

1 Running article perhaps subject to trial? (7)
5 Again flick back whip (6)
9 Has Olympian formerly lost heart? (4)
11 Ham risotto moulded with cup (10)
12 Muse caught by crude backing (4)
14 Net damages BBC owe (6)
16 Parisian to go across one French river (6)
17 Readily faint when wife leaves (4)
20 Mean to involve London College of Energy? (7)
21 Supplementary rent, one I returned (7)
23 About to...