Cryptic crossword No 3,975

Across

1. Follow dog circuit (5)
2. Race to dictator's summit (4)
3. Terseness regularly seen in deal? (5)
4. Racing team initially admits alternative fraud (4)
5. Following crash, German broadcaster discloses race number (7)
6. After training, each type gets item of clothing worn by 26 (3,5)
7. Posh Charlie, bitten by friend, comes to medical compound (6)
8. Rider's garb scared cattle (6,6)
9. Outspoken European in Grand Tour (4)
10. Horny African's natural aroma overpowered by stench! (6)
11. Prolong ride (4,3)
12. Club staff provide tough competition (7)
13. Yikes! The French are after me! (5)
14. Trace of iodine? No thanks! (4)
15. Noted French tower in castle field best viewed East to West (5)
16. Extract from bioengineering oestrogen forms traditional performance-enhancing drug (8)
17. Pirate in short trousers? Back in area! (7)
18. See 27a

Down

1. Much regret, on reflection, in French capital (5)
2. In France, good to override first signs of aunt and sister in asking: "How's your father?" (7)
3. Tour de France scorers find power station in Berlin (9)
4. He lazed cycling up punishing Alpine climb (4,5)
5. Former team sponsor starts to mandate all personnel exercise intensively (5)
6. Temporarily close once could be this? (4,3)
7. Gilbert our male tabby hiding in mountain pass? Au contraire! (9)
8. My toy Lego bananas reveal true meaning (9)
9. Following International, Spain have utter lack of will (9)
10. Before the Spanish retired, jumper needed in shade (7)
11. Andy Schleck, originally pumped with MDMA and speed, injects oxygen! (7)
12. Swimmer scratching backside uses indoor training aid (5)
13. Aroused by cryptic lines articulated (5)