Boris Johnson will become a father again at the age of 55 when fiancee Carrie Symonds gives birth in early summer. Here two writers, John Laverty and Alex Kane, who became parents in their 50s, write an open letter to the Prime Minister, telling him what to expect.
They never tell you about the guilt, mate. Shock, pride, 'old codger' jokes ... check, check, ha-bloody-ha. But guilt? That wasn't part of the expected maelstrom.
It was there, though, after the initial excitement morphed into the stark realisation that a new life had begun and yours was about to change forever. But when you're my age, 'forever' feels rather finite.
That's where the guilt comes in. I'd heard of 'older' first-time parents being accused of selfishness because they 'won't be around' when the child is still relatively young.
Well, thanks for that cheery thought. But, having relished the first milestones, I intend to still 'be around' for many others - even more so on recalling Soley's tears when the Grim Reaper knocked on my door a couple of years ago and, mercifully, didn't force his way in.
You're a parent already, Boris, of, erm, several children but you haven't experienced being in your fifties when a new one comes wailing. Chances are, with your high profile, you won't have folks coming up to you in the street to say what a lovely grandchild you have, and not knowing whether to feel flattered or insulted.
People in school, however, might notice how smart your little nipper is; apparently, children born to older dads are more likely to have high IQs and, given your Eton and Oxford-educated genes, BoJo Junior's set to be a genius.
Also, a recent study suggested that older parental chromosomes can lead to longer life spans in the children. Which is good news for them but not necessarily us, Boris.
Best, therefore, to stay on the diet Carrie put you on when you were vying for the Tory leadership.
It's not just the younger, fitter missus who has to fret about weight issues after a birth, but perhaps it's nature's way of suggesting that, if you do want to see the little one grow into a big one, pay as much attention to your own health as theirs.
My erstwhile co-party-animals might be surprised to learn that my biggest vice these days is Haagen-Dazs ice-cream, and that the last time I was still awake at midnight was on New Year's Eve.
New Belfast restaurants went out of business before we'd got a chance to darken their doors; I think we discovered 'self-isolation' long before anyone else.
And, despite your notorious reputation, Boris, on the romance front, studies have shown that, although kids can test even the strongest relationships (what with keeping one or both of you up all night, or suddenly transforming from sweet little creature to surly teen), 'more mature' parents are better at supporting each other through highly stressful situations.
They're also likely to be more financially secure than younger counterparts, for whom the horrendous cost of, among other things, childcare, can be hugely taxing. Not only that, but if it's taken you this long to become a parent, your appreciation of the newbie is set to be even deeper and - if you can avoid spoiling the little mite - your offspring will be less prone to behavioural or emotional problems later in life.
None of this was discussed pre-Soley.
I was the wrong side of 50 and although a child was biologically possible - Claire's considerably younger - we didn't regard it as likely.
Indeed, during a holiday in Cape Verde in 2013, and while reading an Icelandic novel called The Silence of the Sea by Yrsa Sigurdardottir, I came across a minor character called 'Soley'.
"That's a lovely name for a girl," remarked Claire, adding: "I must mention it to my sister..."
Two weeks later, we discovered that Soley - it means 'Sunshine' - was on her way towards brightening our lives.
Obviously I can't make myself any younger, so the challenge now is to look as cool as possible. You can sing along to Into The Unknown, but no daddy dancing - ever - at the numerous kiddie birthday parties. Even twentysomethings look soooo uncool doing that.
At just five-and-a-half, Soley doesn't yet get it that her oul' boy is actually ancient, nor that I'm no longer pretending to get beaten by her in a race to the next lamp-post.
Sadly, there may well come a time when she's embarrassed by my advancing years - as I, shamefully, was at times with my own late-in-life parents.
Hopefully, however, I'll still be around when that era passes and she realises her prehistoric padre did his best for her - and is currently doing his best to keep up with her.
As one of your predecessors at Number 10, Gordon Brown (who, like me, became a first-time dad in his fifties), remarked on leaving office: "Being Prime Minister was the second most important job I could ever hold..."
Like you, I'm required to wear suits quite a lot and I've turned up at many events with bits of porridge, yoghurt, banana, custard, honey and peanut butter sandwiches stuck to me. All babies seem to be natural snipers when it comes to targeting the stuff they don't want to eat towards your lapels, ties, shirt collars and trouser fronts. Better still, they have an unerring ability to land the most objectionable, difficult-to-remove stuff just as you're waving goodbye and don't have time to change. Wear it as a badge of honour.
And let's not get started on the snot, vomit, ear wax and disjecta membra of an impossibly overstuffed nappy which is part and parcel of sharing the house, or Downing Street flat, with a new baby. They're noisy, temperamental, difficult to control, prone to pointless rants and capable of covering the place in poop at any and every moment. But as Prime Minister and leader of the Conservative Party, you'll recognise most of this behaviour from your everyday contact with politicians and assorted divas - so you'll be well prepared.
Yet at the end of the hardest of hard days, or the beginning of a day you just know is going to be difficult (a backbench rebellion springs to mind), there is nothing to lift your spirits like the smile of your baby. That sense of wonder in the eyes (albeit it could also be something to do with spotting a space to project the frogspawn-like liquid which usually accompanies the latest burp); the awkward, squiggly grin of recognition; the hesitant uncurling of the fingers, followed by a floppy wave (it's the sort of thing grown-ups also do when confronted by a Prime Minister during an election campaign); and that gurgling, purring noise all babies make when a besotted parent stares at them. It's called joy. Pure, undiluted joy. And there is nothing to match it when you need to wind down.
What I've found as an older dad is that babies bring a much-needed balance to my world. Or maybe counterbalance is a better word to use. I spend most of my day observing politics in Northern Ireland (which, to be honest, is an increasingly depressing way to spend any day, let alone almost every day), hoping to spot reasons to justify even a very small dose of optimism. I tend to end most of those days shaking my head, yet hoping, like Mr Micawber, that "something will turn up". Sadly, the something that turns up is usually much the same as the stuff that came before. But spending so much time with my children allowed me to spot a different kind of hope: the hope that the love, confidence, support and stability they get from me will make them rounded, caring people who will look for the best outcomes and work for the best outcomes.
As I've grown older I've also learned to spot the errors of my past and recognise things that I would have done differently if I'd had the chance. That's what's so comforting about a baby when you're older. You already know what you want to do, or do differently. For me it is about time. Choosing to be with them as much as possible. Choosing to begin and end the day with them. Choosing to leave them to school and pick them up again. Choosing to be there for the first steps, first words, first use of a fork, first holding a glass on their own - first everything, in fact. Choosing to work around their lives rather than expect them to work around yours.
Prime Ministers are, by the nature of their job, figures of enormous authority and influence. They can set standards of behaviour which others will choose to follow. They can become role models, for the most unexpected reasons. Their behaviour in Downing Street isn't just measured by their political decisions. It is measured, too, by their private life.
You have an opportunity to prove that older dads (and there is still a stigma around them) are just as good as younger dads. And you also have the opportunity to show that the life of any busy parent can and should be built around their children. As a society we need to learn to prioritise the importance of the family bond rather than just focusing on careers, income and reputation. Strong families are the building blocks of stability and I think too many politicians have lost sight of that reality.
Anyway, while we may disagree on many things, I wish you well with the new arrival. Children are always a blessing. And for older dads, with more experience and a willingness to make the time for them, children are a particular blessing. Good luck,