It’s my fortieth birthday, a Friday. We’re halfway there, as Bon Jovi once sang, and it’s all a bit underwhelming. I don’t feel 40. Nor, scrutinising myself in the bathroom mirror, do I think I look 40. A very subtle sprinkling of grey, but we’re talking individual hairs rather than distinguished patches. A hint of baggage under my eyes, kept at bay by daily application of Rio Rosa Mosqueta, a miracle oil extracted from the hip of a wild South American rose which may or may not work - how am I ever to tell? It claims to improve the freshness and texture of the skin, ‘to help prevent it ageing prematurely’. It also ‘attenuates the appearance of crows’ feet, wrinkles and skin blemishes.’ Had I not gently massaged an oily drop under each eye with my little finger every morning for the last five years perhaps I’d look like Barry Norman.

Barry Norman turned 40 in 1973, before I’d even started watching him religiously on telly.

Happy birthday to me. And happy birthday to Paul Stock of East Hunsbury in Northamptonshire. I received an email from Paul exactly one year ago today. I’ve never met him and I don’t know what he looks like. Having read my first book, Paul got in touch via my website to tell me we are doppelgangers. He too was born in ‘good old Northampton,’ as he put it. We share the same date of birth, 4 March 1965. Paul was born at 6pm, three hours before me. It was snowing that day, the one fact I’ve always carried with me.

Paul continues: ‘I lived in the Headlands until 1979 and then we moved into the new development around Wellingborough Road, town centre. My Mum is still there now, my Dad having sadly passed away three years ago. I live in East Hunsbury with my family and commute to Milton Keynes every day where I earn my crust.’

He signs off by wishing me a sincere and heartfelt happy birthday. What a nice man. He, too, is halfway there today. I wonder what it means to him. He mentions family which denotes kids. I feel sure that family alters the existential coordinates for the man on the cusp of turning 40. It means you have fulfilled the purpose for which God put you on earth. Unfortunately I don’t believe in God and that our purpose here on earth is to look after it. I have no kids.

They say that life begins on this day, but what they mean is that it begins ending. Because I don’t believe in God I will probably be dead in 40 years’ time, or at least coming to the end of what they’ll be forced to call a good innings. Will my death make the papers? My birthday hasn’t yet made it into the Guardian.