The Kidnapped Prime Minister. Agatha Christie

Towards the end of the First World War, Hastings calls on Poirot in his rooms to discuss the sensational news of the day – the attempted assassination of the Prime Minister, David MacAdam. They are interrupted by two visitors: Lord Estair, Leader of the House of Commons and Bernard Dodge, a member of the War Cabinet. They enlist Poirot to help with a national crisis – the Prime Minister has been kidnapped.