I’m in the far north of Finland. The sky is a perfect blue; beneath it, a few feet of ice lie between me and the black depths of Lake Inari. I’m part of a crowd, a thousand or so strong. We watch. We wait. Whoosh! Huff! Crunch! Half-a-dozen panting reindeer fly by, each pulling a jockey, crouched low over cross-country skis.

I’m here to make a Christmas radio documentary for the BBC World Service about reindeer racing, a big thing in the Arctic Circle. Every spring, communities get together in forest clearings to watch reindeer haul riders around 1km circuits. The gathering on Lake Inari is the final meet of the Finnish season; it’s here that the fastest 24 animals race to be crowned The Reindeer King.

The lake covers 1,040km of some of the most remote, sparsely populated territory in Finland, forming a vast natural arena amid the forest. But the track, carved a few days earlier by snowplough, is only a 20-minute walk from one of the few population centres in the region, the little town of Inari – which makes it easy to sneak back to the hotel to warm up with a coffee or a sauna.

During the rest of the season, the reindeer and their jockeys race in groups of four to six. But on Championship Sunday they whizz around a longer, 2km circuit one at a time, against the clock. The world record at the distance – 2 mins 26.90 seconds – belongs to a reindeer called Eurokas, set in 2005.

Trainers spend many hours a day with their animals. ‘A good race reindeer has to be strong and fast, but it also needs a big heart for blood circulation and big lungs,’ Juhani Lakela tells me. His family has been herding reindeer since the 1600s. ‘And of course, the mind ...’ I hear a lot about reindeer psychology during my trip. Good racers are alpha animals: wild, crazy, strong.

Sometimes, racers can be too independent. It’s not unusual for a reindeer to get halfway around the course and then jump off the track and make a break for the forest. ‘With horses you can be a leader and tell them what to do,’ says Anne Ollila, director of the Reindeer Herders’ Association. ‘With reindeer you have to negotiate.’

Championship weekend, which takes place on 1-2 April 2017, is a big social event for the reindeer herding community – a chance to catch up after the long winter. Little kids in over-size sunglasses are pulled around in sledges like tiny rock stars. A group of older reindeer herders in huge furry hats chat as they browse the merchandise at the cow-bell stall. The snowmobile stand is popular: herders examine the paintwork and check eBay prices on their mobile phones. There’s food everywhere: I try reindeer sausages and reindeer stew; but my favourite is a rye bread sandwich containing potato salad, sautéed reindeer and lingonberry sauce.

There are just a few tourists among the crowd, but I have a hunch that’s going to change. Spread out along the lakefront, Inari is a peaceful, empty place. It’s not accessible by direct flight but the Visit Inari office in the centre of the village runs activity packages: aurora hunting, winter fishing, husky trips, sleigh rides, snowmobile expeditions. Siida, a big complex on the edge of town, is home to the Sami Museum and Northern Lapland Nature Centre, and has a cosy café.

Hotel Inari is closest to the championship action, in the centre of the village with lakeside views. It’s smart, modern and some of its rooms have private saunas. But my choice is Hotel Kultahovi, run by the Nikula family for nearly 50 years. It’s smaller but rooms have ‘aurora cams’, so you can keep an eye on the sky without freezing your toes off.

The hotel restaurant, Aanaar, serves the best food in town, combining reindeer with flavours like chocolate and pine, and making use of locally foraged wild greens, lichen, fungi and berries. Lightly smoked reindeer heart is a typical main, served with marinated root vegetables, juniper, horseradish yoghurt and pine moss; desserts include chocolate fondant with spruce needle ice-cream.

Aanaar also hosts the big party on championship weekend. The reindeer herders slip out of their ski suits and furry hats into smartly ironed shirts; moustaches are trimmed and shoes polished. A crooner in his 60s presides: this is Eero Magga, famous for his big hit, The Reindeer Herder’s Kiss. As the accordion pumps, the herders bob up and down and round the dance floor; I’m taken for a twirl by a chap in his 30s with perfect manners and a good-size herd.

At midnight I slip outside into the frozen car park. I take a step and put a foot straight through the thawing ice and into three inches of freezing water. But that doesn’t matter ... up above, waves of green, purple and red flicker like fire. It’s the perfect end to the perfect Arctic adventure – the northern lights.