Agent Running in the Field by John le Carre

The British spy thriller at its unputdownable best Observer Nat a veteran of Britains Secret Intelligence Service thinks his years as an agent runner are over. But MI6 have other plans. To tackle the growing threat from Moscow Centre Nat is put in charge of The Haven a defunct substation of London General with a ragtag band of spies. His weekly badminton session with the young introspective Brexithating Ed offers respite from the new job. But it is Ed of all unlikely people who will take Nat Paperback softback