It’s a strange thought that, fourteen months ago, I was getting ready for the publication of Murder Most Unladylike. I wasn’t sure what the world was going to make of my book, and of Daisy Wells and Hazel Wong – and I don’t know what I was expecting, but it certainly wasn’t this.

Here I am, just over a year later, and I have somehow become the author of three books, with another on the way, and my series is sitting on tables (sometimes on tables of its own), and Murder Most Unladylike won a Waterstones Prize and is going to be published in France and Germany and Taiwan (and is already published in America, as Murder is Bad Manners). And, more important than any of that, Daisy and Hazel have jumped from my brain into yours, and it seems like you want to keep them there. I’ve said this several times, but I can’t help but keep on being amazed (and a bit alarmed) by what’s happened to my life. I think this is probably a dream – but a very nice one, which I hope will last a while longer.

Today is the official publication date of First Class Murder – it is now absolutely and irrevocably a book, and you can find it in any good book store. In their world, Daisy and Hazel are half a year older than they were in Murder Most Unladylike, (probably) a little bit wiser, and also (in Hazel’s case) a little bit braver. They’re on their summer holidays, and Hazel’s father has decided to take them on a railway adventure across Europe on the Orient Express. But, of course, wherever Hazel and Daisy go, death seems to follow, and in this book they have to face not only a dead body, but an impossible murder and an international spy.

I went to see the book in store on Tuesday, in Oxford Waterstones, and it really does look fantastic. The orange cover is completely unmissable, and totally insane in the best way. The three books look so great together, too – so much thanks to my design team at PRH and my illustrator Nina Tara, as always.

I had an amazing time writing First Class Murder – I think it’s my favourite book of the series so far – and I can’t wait to hear what you think. I’m only a little nervous. So send me an email, or a tweet – bonus points if you include a photo of you with the book, or the book and a nice bunbreak. I had an extremely upgraded one in celebration – and there will be more celebrations in order today! Happy birthday, First Class Murder. Here’s to many more!