Greenmantle is the sequel to The 39 Steps but there is much more to this book than the previous one. Set in 1915, Richard Hannay is recuperating at Furling country house in Hampshire after having been wounded at the Battle of Loos. He is expecting to be given command of his own battalion but when he gets a telegram from the Foreign Office, he ends up working undercover with others.

Sir Walter Bullivant has already lost his son on the same mission. When Harry Bullivant died he had 10 bullets in him but managed to say one word ‘Kasredin’ before he died. With just a few more clues Richard Hannay takes up the trail.

Going undercover as a South African Boer who hates the English, Hannay pretends to be on the side of the Germans, who are planning to stir up revolt amongst the Muslims. He is aided by three others, Peter Pienaar a South African, John S. Blenkiron an American and Sandy Arbuthnot a Scot.

First published in 1916, this book has a much more convoluted storyline than The 39 Steps. As you would expect from an adventure/spy novel which is almost 100 years old, it contains rampant racism, homophobia and sexism but this doesn’t detract from the enjoyment of the story.

As you can imagine, Greenmantle was a huge bestseller during the First World War.

Given the state of the world today, nothing much seems to have changed in all that time, except we aren’t fighting Germans now.

The writer Allan Massie said ‘Maybe Greenmantle should be a set-book for our security services.’

It could only help – they need something.

An enjoyable adventure story.