CRYPTIC CROSSWORD No. 16,858

ACROSS: 6 Ordnance Survey. 9 Smithy. 10 Ambience. 11 Announce. 13 Lessee. 15 Ratify. 17 Malawi. 19 Scarce. 20 Idealist. 22 Civil war. 24 Tonsil. 26 Intelligentsia. DOWN: 1 Common fraction. 2 Adit. 3 Banyan. 4 Isabella. 5 True. 7 Chapel. 8 Ecclesiastical. 12 Otter. 14 Shawl. 16 Free will. 18 Oil rig. 21 Extent.