Roman helmet 'would be huge draw' for Cumbria
Tourism chiefs believe keeping a rare Roman helmet in Cumbria would result in a £3m boost for the area.
The helmet was found by a metal detector enthusiast in Crosby Garrett, near Kirkby Stephen, in May.
It will be auctioned by Christie's in London on Thursday, where it is expected to fetch £300,000.
Carlisle's Tullie House Museum is bidding to keep the helmet in Cumbria and has been running an appeal to raise money to fund the campaign.
The helmet is believed to be one of only three of its kind to be found in Britain.
'Mona Lisa effect'
Cumbria tourism leaders believe the helmet would become a major draw for visitors.
They said it would be a highly significant acquisition for the museum's Roman archaeology collection.
Eric Robson, chairman of Cumbria Tourism, said: "You only have to witness the public appetite and media interest to see how this could transform awareness of Carlisle and its place in Roman Britain.
"If the city can secure it, there is a real opportunity to create a Mona Lisa effect where visitors coming to Cumbria won't want to leave the county without having visited Carlisle to see it."
Tullie House has to raise at least £80,000 in donations to unlock funding from other organisations.
Last week, an anonymous businessman pledged £50,000 if the public matched the amount.
Museums manager Hilary Wade said: "There are only a few days left to raise the money and we face a David and Goliath battle, because no-one really knows how much it will sell for.
"If it is financially realistic to bring this extraordinary helmet back to Cumbria, then we will do all in our power to do so, but it will not be easy."
The helmet would have been worn, possibly with colourful streamers attached, as a mark of excellence by Roman soldiers at sport parades.
It is believed that Romans wore the helmets as a mark of rank or excellence in horsemanship.
Similar helmets were found in 1796 and 1905.