Moonwalker - Adventures of a Midnight Mountaineer

SPENT the last 24 hours wishing I was 33 again. Maybe it was 25. Or perhaps 41 or 36, even 50.

This feeling hasn't suddenly been brought by a desperate longing to turn the clock back, nice though that would be. It's about mapping your age. Or to be more precise, matching your age to the corresponding Ordnance Survey Landranger map number.

The seed was planted by mountain guide Graham Uney and his partner Sharon Kennedy. And like so many of the best ideas, the genius is in its simplicity.

There are already plenty mountain lists and challenges to go round but for those looking for something slightly different there's always room for one more. Graham, who runs the Lake District-based GU Mountaineering, had been wondering about buying one OS map and then climbing every Munro, Corbett and Graham on that sheet over one year. His lightbulb moment was further illuminated by Sharon, who suggested that the map number should match your age. 

The innovation was floated on social media and the immediate reaction suggested it had caught the imagination. But not all maps are equal. There are ones that are wall to wall with great peaks, others with just one or two. And there are the ones that have less land than sea.

Graham turns 50 next year, so he's happy with his lot: his matching sheet is Glen Orchy and Glen Etive. No lack of mountains to choose from in these areas. Happy Birthday also to anyone who will be 25, 33, 36 or 41, while, depending on how you view Skye's Black Cuillin, being 32 will either be a jackpot or the worst present ever.

It would appear to be a great game for those from mid-teens to mid-50s. I shouldn't imagine there will be many pre-teens out bagging on their own, so it's the more elderly among us who will be the most severely handicapped.

My initial excitement at a new challenge dimmed somewhat when I realised my sheet covered the Edinburgh area. Unless there has been a major topographical blunder which has gone unnoticed for the last few thousand years, there are no mountains in our capital. I consoled with the idea that I could run up Arthur's Seat and then just go for a pub crawl. Then came Wednesday's restrictions announcement, and even that idea was dead. Touring various parks with a bottle to shout at the pigeons looked like becoming the default position.

Then I realised I had forgotten my own age. The Edinburgh map would have covered this year; next year's would slide one along and much of that sheet is in the North Sea. Damn. Never mind, I shall be checking for underwater peaks, just in case.

Others feeling slightly envious are already looking at ways to circumvent the 'rules' while sticking to the spirit of the challenge by subtracting or adding a certain number of years. And of course there are always those that tell little fibs about their age anyway. Maybe you could revert to dog years, or even just pass the challenge on to your dog as a special birthday treat.

Of course, this doesn't have to be an immediate take-up. Those a year or two away from matching a plum area could just hold off. Again though, this won't work for the more mature: once you get below OS sheet 56 it's likely to be purgatory in the 70s or nothing at all. Perhaps a Benjamin Button style approach could be considered.

As well as being a bit of fun, however, there is a more weighty side to this idea. Any initiative that promotes and encourages navigation skills is to be welcomed, and Graham is hopeful that some of our mountaineering bodies will get behind it.

Even with all the modern tech available, anyone out on the hills should be able to use a map and compass. There have been too many incidents in recent years where an over-reliance on mapping apps has turned out to be the weak link.

It will be fascinating to see how many people take this idea and run, or rather, walk with it. Mappy Birthday everyone.