Diary: Patrick Hennessey

I’d take Helmand over Westminster any day

I'm either more honest or more shallow than other first-time writers I have spoken to recently (perhaps both), because while I agreed with them about the thrill of seeing your finished book for the first time, or the nervous pause before reading a first review, what I'd been looking forward to most was a launch party. The spate of articles lamenting the "end of the book launch" had left me concerned that my celebration was going to get "crunched", but the appropriately named Loose Cannon club gave us a military discount and a night to remember.

Civvy and mess friends jostled to see who could do the most damage to the bar, and it was hard to say who was more bemused, the senior officers being quizzed by the arty student types, or the wonderful girls from Penguin being chatted up by the squaddies. As the differing crowds mixed seamlessly before stumbling off into the night, I stayed just about sober enough to realise that the whole point in writing the book had been to try to bring these occasionally too separate worlds together. If the book is half as successful as the party was, I'll be a happy man.

Unknown to me, at about the same time as the book launch was winding down, friends who hadn't been able to make it because they were in Helmand were launching Operation Panther's Claw. Afghanistan was thrust into the headlines, and the book had new relevance. The past few weeks have been a blur of interviews and phone calls. Soldiers don't often get the chance to voice their opinions in the media and it's been fun phoning all the boys to find out what they're thinking before popping up on Newsnight next to incredulous-looking colonels. I started one weekend in Bath reviewing a computer game that claimed to be the most realistic war game ever (neither hot nor dangerous enough) and ended it on a BBC sofa with the Home Secretary and shadow chancellor. From the sublime to the ridiculous, though I'm not sure which was which.

For all the excitement of the studios, the discussion has often been too sad or too serious for the experience to be "fun". I came closest to slipping into my long-since-discarded "angry officer" mode when I nearly snapped at an AP journalist who'd asked me to speak about yet more casualties on the evening news. After a lengthy discussion about the importance of getting news from Afghanistan to a wider audience, he phoned back to say the item had been dropped in order to cover something about papers tapping celebrities' phones.

Fortunately, the wider public is not so cynical. Chorleywood Bookshop, a wonderful independent bookseller not far from where I grew up, agreed to host my first "author event". On the pretty, suburban train ride out, I felt almost as nervous as when sitting in the back of a Chinook, if more comfortable. Thanks to ample refreshments, the evening was a success, and the genuine interest of those who came convinced me that the book had been worth writing. A few days later at Daunt, London's own "local" bookshop, things were going equally well - until someone asked if I'd consider a career in politics. I'd take Helmand over Westminster any day.

After too much arguing about helicopter shortages, I escaped to the Secret Garden Party, one of the smallest and best of all the summer festivals. Taking a quick breather from the Temple of Excess and looking out over the lake around which the bacchanalia unfolds, I remembered how two years ago I'd been there on R&R from Afghanistan. The theme then had been, appropriately, Apocalypse. This year it was Babylon and Eden, and I lounged in a leopard-print dressing gown instead of an army smock, glad to have made the transition, but hoping for the best for those a long way from such a joyful place.

One who wasn't so lucky was Lieutenant Mark Evison of the Welsh Guards, who was shot and died in May. At dinner with his mother and friends, thinking of fundraising ideas for the foundation set up in his memory, I was struck by how similar his diaries were to those I had kept, and how arbitrary and unfair life can be. His mother hopes the Mark Evison Foundation will give other young people the chance to achieve extraordinary things. Give generously at www.markevisonfoundation.org - I can think of no finer way to pay the debt we owe to young men like Mark.

To a party at Wellington Barracks, a lavish send-off for the Grenadier Guards who soon fly out to Helmand. It's strange walking around what was once home, bumping into familiar faces but feeling now like an outsider, an impostor who'll be tucked up safe in bed while they are out scrapping. Some of the newer men in the mess have read the book and it hasn't put them off - indeed, it's whetted their appetite. I must have done something right.

Patrick Hennessey is the author of “The Junior Officers' Reading Club" (Allen Lane, £16.99). Between 2004 and 2009, he served in the Grenadier Guards, and toured Afghanistan in 2007