Capt. W.E. Johns 
Biggles Takes A Hand [EPUB ebook] 

“If you will go to the Adlon Restaurant in Bank Street, Kensington, today, at a quarter to one precisely, and sit at table number two, you will be joined by someone who will give you information you should be glad to have.—A Well-wisher.”

“You can’t come to much harm in Kensington, ” Bertie said. But this anonymous letter sets Biggles off on the trail of three murderers in a thrilling story of espionage which takes him and the Air Police to West Berlin.