For the festival, the town’s men grow beards and dress as savage Vikings for a torch-lit parade through the streets in the early evening.

It’s a hell of a spectacle, with 2000-odd participants in fancy dress backed up by bagpipes and marching bands playing stirring renditions of local songs.

The climax of the night is when a huge, ornate wooden Norse longboat is set alight, making a giant bonfire in the town’s central park — a tradition dating back to 3000 years ago when a Viking king died and his body was placed in a longship and set alight.

After that, it’s back to one of a dozen venues around town, such as the Grand Hotel, for a 24-hour whisky-fuelled party where different squads from the parade perform skits, songs and shows.

If you’re still standing at first light, don’t be surprised if while you’re walking back to the hostel you get invited into people’s homes to continue the party — and the whisky drinking.

We found ourselves having a liquid breakfast with a bunch of hilarious kilt-wearing bagpipe players from the neighbouring Orkney Islands.

Up Helly Aa is a lot more than a booze-up, though.

It’s a damn fine spectacle and a monster of a party set in a rugged, stunning part of the world, and it eclipses Christmas or New Year’s Eve as the biggest day on the calendar on the Shetland Islands.

What’s more, it’s probably Shetland’s best kept secret, loaded with authenticity because it’s organised by the locals, for the locals.

What you won’t find is a sea of Aussies, Kiwis and Saffas like at other festivals such as La Tomatina or Oktoberfest.

“Aye, it’s not promoted as a tourist festival,” says Shetlander Stephen Mouat, who will lead the parade as the Jarl (or Viking king) in 2009.

“It’s very much a local festival. Of course, we won’t turn anyone away if they want to come and see what it’s all about.”

In fact, we learned how much of a novelty visitors were when our trip in 2008 (the first organised tour to visit Shetland for the festival) rated a mention in the local paper.

And one of my most memorable experiences was meeting an 80-year-old local who insisted on buying me three pints because I was the first Aussie he’d ever met.

It might not be as wild as a good bout of pillaging, but a jaunt to Shetland for Up Helly Aa comes pretty close, and there’s every chance it’ll go down as your most memorable festival yet.

» Trevor Paddenburg travelled with Haggis Adventures (0131-557 9393; An all-inclusive five-day Up Helly Aa festival package costs £449.

Light it up

What is it with the Scots and burning stuff?

It’s not just Up Helly Aa — plenty of their other festivals revolve around pyromania.

» Ancient Fireballs Ceremony, Stonehaven

A unique Hogmanay festival, where at the strike of midnight locals walk through the town swinging mesh and paraffin fireballs above their heads.

» Saint Ronan’s Games, Innerleithan

Locals cart a figure of the devil up a hill and toss it on a bonfire.

» Wickerman Festival, Kirkcudbright

The event’s finale sees the burning of a 25ft tall man made of wicker.

» Hogmanay Torchlight Procession, Edinburgh

Grab a flaming torch and join the throng as a Viking ship gets carried up Calton Hill.