The temperature has hit 40°C in Crete, where I am writing this, and although there have been no fires, nothing is quite how it ought to be. I can’t work out whether this is a great opportunity to get a tan or, effectively, the end of the world. My 60-year-old taxi driver tells me that unfeasibly hot summers were a regular occurrence when he was young and that there’s nothing to worry about. But, he adds, he’ll be dead soon anyway so why should he care?

Right or wrong, this is the paradox at the heart of the climate change debate. Older people, who could be held responsible for the destruction of the planet, don’t need to worry. And young people, who have so much more to lose, don’t really have a say. We invented plastic. They live with it. The anger aimed at two peers elected when they are either side of 30 and the scorn directed at a new MP aged just 25 are misplaced. We have to share power with young people. They’re the ones looking the right way.

Ever since the arrival of my first grandson – Leander Horowitz (the name is Greek: ‘lion man’), born one month ago – I’ve been thinking a lot about old age. There’s something unsettling about becoming a ‘Pappous’, if that’s what I must call myself. I disliked all my grandparents, who seemed ancient and disconnected. I even wrote a book about one of them – ‘Granny’ – a horrible woman who, following an argument with one of her sons, decided not to speak to him again for 25 years. Is Leander going to find me as otherworldly as I found them? Anyway, I’ve already decided on one rule. I will not be called anything that begins with ‘g’. If he wants to be friendly, he can call me Anthony. If he wants to be polite, then it’s going to have to be ‘sir’.

Leander weighed just five pounds when he was born and he really is a miracle. How can fingers so tiny actually work? How did he learn to express himself with that blazing smile? What’s odd is that I find myself worrying almost continuously about the world into which he has been born. Not just climate change but the collapse of the USA, the dominance of China, Russia obviously, the decline of decency and moral values, litter in the streets and so on. Not surprisingly, he hasn’t noticed any of these things – which leads me to the question I’ve been considering more and more. Every generation ends up believing that things are getting worse and worse. But are they? I grew up in the shadow of nuclear war… I was seven at the time of the Cuban missile crisis. I read C.P. Snow and watched the sky for approaching missiles that never arrived. Is it part of the human condition that we need to live with fear?

On a more personal note, I may have written my last children’s book, Nightshade Revenge, which comes out later this year. It’ll be the 14th in the Alex Rider series and I’m happy to have equalled the number of books written by another well-known writer with another famous spy… even if I haven’t quite managed his sales. The new millennium was so exciting, with a whole wave of authors cresting on the success of J.K. Rowling: Philip, Malorie, Eoin, Michael, Jacqueline, Darren – and me. She was the only one without a first name. Who are the new stars? Despite the valiant efforts of one or two journalists, press interest seems to have withered. Mind you, I’m not definitively announcing my retirement. I wrote what was meant to be the final Rider book ten years ago – and have since done four more.

Six weeks from now, a film unit will be arriving in Agios Nikolaos to film Moonflower Murders, a six-part TV series which will be shown on the BBC next year. To thank me for bringing attention (and business) to the town, the mayor has very kindly arranged a special ceremony for me in October. I will be given an award and some of my work will be shown at the local cinema. But will I be able to attend? I’ve been to so many literary festivals this year that I’ve run out of days that I can stay in Europe. Even as the economic misery of Brexit continues to bite, I fight against the soul-destroying pettiness of it all – and here it is in a nutshell. I am being given an honour in Crete but I’m not allowed in to receive it. As much as I love The Spectator, I still don’t understand why the magazine came out in favour. I’ve concealed a message to readers inside this diary. It’s a single word, in Greek.