Comes the Dark — David Stuart Davies

It is 1941 and the city is suffering under the bombardment of the German blitzkrieg. In the darkness of the blackout, Johnny is drawn into investigating the deaths of several prostitutes strangled by a desperate killer. At the same time he infiltrates the Britannia Club, a dangerous underground fascist organization bent on a Nazi invasion of Britain.
As his investigations reach a thrilling climax he is faced with the greatest challenge of his life. This complex and engrossing mystery is told with wit and humour, while evoking the atmosphere of London during the Second World War.