Thanks to NetGalley for a copy of this book in return for my honest review

Ultimatum is a good, solid international thriller with an intricate plot involving a renegade group in Iran developing nuclear weapons. Former Royal Marine Luke Carlton is recruited to MI6 to help identify the risk and contact a source who is bringing evidence of the research out of Iran. The mission goes wrong and soon Carlton finds himself undercover in Iran trying to recruit a new source.

Gardner, a respected journalist, is good at creating a convincing patina of credibility around the story he is telling and there is the usual plethora of acronyms and knowledgeable insider detail. The plotting and the characterisations could be stronger, but overall this is an enjoyable thriller. Good for a long plane flight or a lazy weekend.

Having thoroughly enjoyed ‘Crisis’ I had been awaiting the publication of ‘Ultimatum’ with eager anticipation and I was not disappointed – it’s a worthy sequel. Frank Gardner writes, as you’d expect, with expert knowledge and understanding and takes us through the first official MI6 mission of Luke Carlton, the main ‘Crisis’ protagonist. Torn between personal loyalties, duty and a crisis of international proportions, this is a topical and truly enjoyable tale. Hope our wait won’t be too long for the next instalment.

Excellent hostage thriller from an author who clearly knows his stuff. Lots of technical detail and a plotline where all the good guys do not survive keep one on edge all the way to the action packed finale.

I enjoyed Crisis, the first Luke Carlton thriller and this is just as good and left me on the edge of my seat.

It is a thriller in the true sense of the word as I sped trough the book at breakneck speed as the plot gathered momentum and the loose ends were tied together.

It concerns shenanigans in Iran and the kidnapping of the Foreign Secretary but there are several other strands that link together to provide a meaty and satisfying read.

This series is a winner and the book is highly recommended.