The final episode of Detectorists is "one of the most satisfying conclusions ever"

And yes, this Poundland Time Team is searching for gold, but dig below the surface and it’s about so much more: history, conservation, love, family, friendship, the quiet achievements of ordinary people… these are the treasures of life, not material things.

• Mackenzie Crook explains why this series of Detectorists will be the last
• Where is Detectorists filmed?

It’s a breath of invigorating, unpolluted air and one that makes a sunny virtue of its rural settings (Framlingham in Suffolk masquerading as the fields of Essex). It's naturalistic, quirkily funny and sometimes memorably sad.

The joy of Detectorists is precisely the fact that, for the most part, it isn’t earth-shattering; rather, a succession of entrancing moments and small happenings. And when the final, lovingly crafted episode airs on Wednesday, I confidently predict a deluge of affection for its secret world, and an outpouring of grief that it’s all over.

I say secret because of the bizarre time slot: 10pm on BBC4 is not the greatest way to get your show to catch on. Bar the occasional swear word, there is nothing offensive here. On the contrary, a spirit of kindness permeates the whole endeavour.

The series finale this Wednesday 13th December is one of the most satisfying conclusions ever. Series one and two both ended in clever and memorable ways: bittersweet and punch-the-air respectively. But the series three finale has a real poetry to it; Crook seems to be saying: “Yes, that’s where we’ll leave it – I’m happy with that.”

And that lyricism is appropriate. In its clever, unhectoring way, the comedy draws us aside and asks us to dwell on what really matters. It reminds me of the poem Leisure, by William Henry Davies, which begins:

“What is this life if, full of care,
We have no time to stand and stare.

No time to stand beneath the boughs
And stare as long as sheep or cows...”

Everyone has their moment in the sun – and that brings me to Detectorists’ miraculously good casting. For starters there’s the inspired central pairing of Crook (the series’ writer and director) as nervy archaeologist Andy and Toby Jones as sage forklift driver Lance. Their trivia-laced banter about TV quiz shows, the misadventures of their associates and their “hot rocks and grots” is one of Detectorists’ many incidental joys.

The motivational forces in their lives are their tolerant other halves. Andy's partner Becky (Rachael Stirling) is supportive, funny and forthright. And Lance’s ex, the exploitative Maggie (Lucy Benjamin), gradually leaves the scene to pave the way for his long-lost daughter Kate (Alexa Davies) and work colleague Toni (Rebecca Callard). Both prove to be much healthier influences: kind, caring and able to curb Lance’s penchant for dithering.

There are the oddballs and eccentrics of Andy and Lance’s local society, the Danebury Metal Detecting Club, headed by the buttoned-up but salt-of-the-earth Terry (Gerard Horan), whose wife Sheila (Sophie Thompson) supplies its members with eye-watering home-made lemonade. Don't miss the cameo appearance of her infamous beverage in the last instalment!

There’s the cynical but paternal Russell (Pearce Quigley) and his young charge Hugh (Divian Ladwa), Louise (Laura Checkley) and her quiet but knowledgeable friend Varde (Orion Ben) – look out for a wonderful, almost throwaway scene near the end that will bring a lump to the throat.

And then there are the rival detecting team, Terra Firma, formerly known as the Antiqui-Searchers and the Dirt Sharks. But everyone knows them by their nicknames, Simon and Garfunkel, to whom they bear more than a passing resemblance. As played by Paul Casar and Simon Farnaby, they are the yin to Andy and Lance’s yang, and provide delightfully childish verbal sparring throughout.

Another great strength is that it’s not overwritten. Detectorists is moving not only for what is said but also for what is not.

One of my favourite exchanges is a pub garden two-hander in series two. Lance, nursing a pint, is rueful about the possibility that he has driven Kate away by being overgenerous after years of non-contact. Smiley Sheila, whom we previously thought was naive and a bit simple, consoles him with unexpected wisdom.

“What you’ve got going for you now is that she’s met you, Lance, and you’re… lovely.” Behind her careful words of advice lies a world of sadness – the loss of a child or similar tragedy is never actually specified. It’s beautiful and heartbreaking at the same time.

Speaking of beauty, there are few, if any, comedies as good-looking as Detectorists. Directors of photography Jamie Cairney and Mattias Nyberg have performed cinematic wonders. Each new chapter is framed with a dew-covered cobweb, or a dandelion blotting out the sun, or a ladybird crawling up a blade of grass... All mini works of art, and utterly in keeping with the show’s subtext: “Cherish the countryside – and protect it”. If this series doesn’t inspire you to go for a walk, nothing will.

Tying in perfectly with the images are Johnny Flynn’s lilting, folk-flecked theme tune, “Will you search through the lonely earth for me?”, which, cunningly, has been commenting on the story arc all along.

If all British programmes took this much care over their tone, look and overall distinctiveness, the golden age of television would never go away.

Modern comedies are often predicated on cruelty: laughs are hard, clanging or sharp as barbed wire. In its quiet, undemonstrative way, Detectorists has ploughed its own furrow. Buried in its field of fun are evergreen truths about life, and the things we don’t say but should. So if kindness and companionship are unfashionable, I know which side of the hedge I’d rather stand.

If this truly is the end of Detectorists, then just hand the laptop and the director’s chair back to Crook for a new project, because he clearly knows how to get to the heart of the matter. Working in the movies has given him an eye for a set-up, and being steeped in other people's comedy has enabled him to see what's funny and what isn't.

Detectorists is quite simply BBC4’s greatest hour. Its ratings have been steadily climbing, and the admiration has soared. I had the great pleasure of introducing it to my brother and a close friend, and then receiving excited feedback from both.

With its sly humour and compassionate personality, Crook’s show will easily stand the test of time. Though the appeal was instant – from week one Radio Times said, “Already it feels like a glittering comedy find” – every episode has unearthed gems, delivered by actors who know they’ve made something of lasting value.

Detectorists won the Bafta for best scripted comedy in 2015; if there were any justice in the world, the buzzers would soon be going off for every gong going.

Detectorists concludes on Wednesday 13th December at 10pm on BBC4, and you can catch up on BBC iPlayer