IT IS a show of male-only might as 1,000 men parade through the streets of Lerwick, torches burning and voices roaring, in a celebration of Shetland's Viking heritage.
Now, pressure appears to be growing on the organisers of Up Helly Aa to admit women into the main procession that accompanies the chief - or Guizer Jarl - as he makes the journey to his burning galley boat.
Calls to admit women to the procession in recent years have broadly been met with weary derision from those who are proud of the Lerwick tradition that has become a popular promotional tool for tourism to the islands, with the jarl and his supporters attending events in Edinburgh and New York in recent years.
READ MORE: Billionaire set to transform remote Scottish village into 'community hub'
But it would appear that support for a more gender-balanced event could be growing. A number of shops in Lerwick, which traditionally dress their windows in celebration of Up Helly Aa, have included female vikings in their displays.
Yesterday morning a group called Reclaim the Raven, which references both the Lerwick crest and Norse mythology, pinned an alternative message to the Market Cross in the town at 5am, around an hour before the Guizer Jarl traditionally pins up his proclamation in the same spot.
READ MORE: Scottish fishermen warn UK Government: 'We are not a Brexit bargaining chip'
The alternative message depicts Gna, a messenger of Frigg, the goddess of foresight and wisdom, and asks 'where are your dottirs (daughters)?".
A statement added: "We hope the Up Helly Aa committee would show these and engage with everyone in bringing a bright and inclusive future to this festival that is loved around the globe.
"No one wishes to see Up Helly Aa become better known for the exclusion of woman and girls than for being the biggest and best fire festival in Europe."
A web cam apparently captured two men taking down the Reclaim the Raven message and putting it in the back of a van around 8am yesterday.
Zelda Pennington, of the group, said attempts to get women into the main procession were 'stonewalled' by the Up Helly Aa committee. Another group, Up Helly Aa for Aa, is also active in campaigning for the inclusion of women in the event.
READ MORE: Scottish children's hospice gifted huge Loch Lomond estate plus one million pounds
Ms Pennington said: "Rather than be confrontational - and we really didn't want to cause any damage to an important festival to Shetland - we decided we wanted to do this alternative message and create something attractive instead."
She said: "Our main concerns are that Up Helly Aa also has a junior festival in the schools so children are getting exposed to this exclusion of girls at a very young age, at a primary age.
"This year they couldn't get enough boys from Lerwick to take part so instead of opening it up to girls from Lerwick, they opened it up to boys from all over the islands."
Other Up Helly Aa festivals in Shetland include women and girls in the event.
She said: "Some festivals have made a choice of being inclusive. Some are concerned that these ideas of gender exclusion are being re-imported into their areas.
"We are also concerned how it impacts on the community and the values within that community."
READ MORE: Scottish workers rake through bins to find woman's life savings hidden in Bisto tins
Some believe that women should hold their own Up Helly Aa given that the 1,000-strong parade is now at saturation point.
Up Helly Aa first started in the 1820s and was loosely tied into the old celebration of Yule. It latterly evolved into a celebration of Shetland's Viking heritage.
In 2015, Lesley Simpson from Maywick became Shetland's first ever female Guizer Jarl when she represented Bigton and Levenwick for the South Mainland Up Helly Aa.
The Lerwick Up Helly Aa is referred to as 'transvestite Tuesday' by some given some of the jarl squad dress up as women for the event.
Shetland Isles Council, which gives no funding to Up Helly Aa, puts on a civic reception for the Guizer Jarl every year with the day after the event a public holiday in Lerwick.
Malcolm Bell, Convener of Shetland Islands Council: “Lerwick Up Helly Aa continues to be an event which draws large numbers of people to Shetland and is widely enjoyed and supported in the community. I recognise that there are some strongly held views on both sides of this debate. Lerwick Up Helly Aa is a privately run event, run by the community, and the format is therefore a matter for their organising committee.”
The Up Helly Aa was contacted yesterday (Tuesday) but no one was available for comment.